Error serving Ember app after updating via ember-cli-update

Hi,
I am updating an ember app from v3.17.3 to v3.24 (the LTS version). Mac OS 10.13.6. I ran

ember-cli-update --to ~3.24

So far so good. After resolving a few merge conflicts and running npm install, I have

ember --version --> ember-cli: 3.24.0

But when I try ember s locally I get

...
Build Error (broccoli-persistent-filter:EslintValidationFilter) in integration/components/analytics-charts-test.js

ESLint configuration in /Users/user1/Documents/embApp/warlord/.eslintrc.js is invalid:

• Unexpected top-level property "overrides[0].extends".

Stack Trace and Error Report: /var/folders/n5/3gg0dqt57j317n_z9lkv7xfw0000gn/T/error.dump.6c67c97dfe3fcbd6a826413d05601c39.log

The log file is attached. .eslintrc.js is attached.
log.txt
eslintrc_copy.txt

The analytics-charts-test.js file has nothing but the auto-generated test code. I did not write a test for that component.

Reverting .eslintrc.js to it's pre-update content (or just commenting out the extends: ['plugin:node/recommended'], does allow it it proceed past the initial point of failure, but then it gives

/@ember/test-waiters/types/index.ts: Property specifiers expected type of array but got null

Also, running code-mods makes no difference. Same error when trying to serve. Note that code-mods fails at ember-test-helpers-codemod, although that doesn't stop the rest of the mods from running.

Appears that there is some issue in the download for 3.24, perhaps around ember test helpers? Anyone else seeing this? If someone can help, it would be much appreciated.

Thanks

Start by reproducing with ember s after ember-cli-update --to ~3.24 and inspect the attached log and .eslintrc.js, focusing on the reported overrides[0].extends validation error. Compare the generated integration/components/analytics-charts-test.js path with the later @ember/test-waiters/types/index.ts error; done means identifying whether the update introduced incompatible configuration or dependencies and documenting a reproducible fix.