Edit Contentlet button not working in UVE

Problem Statement

While attempting to edit a blog in the UVE on the demo site (local instance), it displays this button:

This button does nothing, as far as I can see, and does not raise any console errors when clicked.

There is a console error on page load; not sure if it corresponds to this per se:

ERROR TypeError: Cannot read properties of undefined (reading 'contentDocument')
    at p.Qn (chunk-PQTHEN54.js:38:10847)
    at p.onIframePageLoad (chunk-PQTHEN54.js:17:9710)
    at chunk-PQTHEN54.js:38:13643
    at tf (chunk-IRNCPZXM.js:8:106146)
    at o (chunk-IRNCPZXM.js:8:106331)
    at HTMLIFrameElement.<anonymous> (chunk-PTQL3SJC.js:2:28587)
    at v.invokeTask (polyfills-E7XIBAE5.js:1:7078)
    at Object.onInvokeTask (chunk-IRNCPZXM.js:8:29812)
    at v.invokeTask (polyfills-E7XIBAE5.js:1:6999)
    at h.runTask (polyfills-E7XIBAE5.js:1:2432)
handleError @ chunk-IRNCPZXM.js:8

Steps to Reproduce

• Open demo site either at demo.dotcms.com or a local instance with a fresh demo starter
• Open the Site > Pages tool and open any blog in the UVE
• Click the Edit Blog button at the top
• Nothing happens

Acceptance Criteria

Button should allow editing of relevant URL-mapped contentlet.

dotCMS Version

25.01.30

Proposed Objective

Reliability

Proposed Priority

Priority 2 - Important

Reproduce the issue in the UVE using the Site > Pages tool and an URL-mapped blog, then inspect the Edit Blog button and the reported iframe console error. Done means the button opens editing for the relevant URL-mapped contentlet without the current no-op behavior.