Front-end cache invalidation processes all WAGTAIL_GUIDE_LANGUAGES locales

When translating the whole site to a different locale at once, we currently submit 29 pages for translation. This is timing out (Heroku level or WSGI worker level, not sure), even though this is quite a small amount of pages.

I believe this is likely due to the front-end cache invalidation, which seems to target all WAGTAIL_GUIDE_LANGUAGES entries.

Sample logs for one page:

[wagtail] Page created: "Explanation" id=248 content_type=core.ContentPage path=/home-3/explanation/
[wagtail] Page edited: "Explanation" id=248 revision_id=766
[wagtail] Page copied: "Explanation" id=248 from=10
[wagtail] Page edited: "Explanation" id=248 revision_id=767
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/af-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/af-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ar-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ar-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/az-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/az-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/be-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/be-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/bg-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/bg-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/bn-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/bn-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ca-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ca-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/cs-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/cs-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/cy-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/cy-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/da-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/da-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/de-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/de-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/el-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/el-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/en-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/en-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/es-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/es-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/et-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/et-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/eu-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/eu-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/fa-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/fa-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/fi-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/fi-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/fr-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/fr-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/gl-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/gl-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/he-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/he-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/hr-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/hr-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/hu-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/hu-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/hy-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/hy-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/id-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/id-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/is-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/is-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/it-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/it-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ja-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ja-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ka-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ka-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ko-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ko-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/lt-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/lt-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/lv-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/lv-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/mn-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/mn-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/my-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/my-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/nb-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/nb-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/nl-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/nl-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/pl-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/pl-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/pt-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/pt-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/pt-br-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/pt-br-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ro-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ro-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ru-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ru-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/sk-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/sk-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/sl-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/sl-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/sr-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/sr-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/sv-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/sv-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ta-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/ta-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/th-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/th-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/tr-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/tr-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/uk-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/uk-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/vi-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/vi-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/zh-hans-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/zh-hans-4.1.x/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/zh-hant-latest/explanation/
[wagtail.frontendcache] [default] Purging URL: https://guide.wagtail.org/zh-hant-4.1.x/explanation/
[wagtail] Published: "Explanation" pk=248 revision_id=767

This might be more of a Wagtail / Wagtail localise issue.

Reproduce translating the whole site to another locale and inspect the front-end cache invalidation path around WAGTAIL_GUIDE_LANGUAGES, using the sample logs as the expected behavior to investigate. Done means locale translation completes without timing out and cache invalidation no longer processes unnecessary locale URLs.