When trying to add best bets through the epi backend, it's unable to correctly load the page tree, and throws a JS error. See screenshot: https://imgur.com/Oytw0Pe
The JS error says "The store was queried with a [string] but the entity id is a [undefined]"
This was working before, not sure what changes may have caused this issue.
Using Episerver v22.214.171.124
The issue is already reported and fixed in the CMS-12314 release with version EPiServer.CMS.UI 11.13.1.
Can you re-check on block level as describe in the release notes, if it is not fixed then report to Epi?
This was fixed by clearing the browser cache. Thanks.