User blog comment:MisterWoodhouse/Social Activity, the 2010 Editor, and Unpausing Migrations/@comment-39885705-20201002202127/@comment-1807002-20201002214918

Sync'ing issues shouldn't effect you- if you haven't been going back and forth to legacy/UPC wikis. It's only if you edit preferences/edit in both Legacy and UPC wikis.

Example: I go to a UPC wiki- edit preferences to source mode, then go to a legacy wiki (wrong editor will be set up a legacy wiki). I go to a legacy wiki- edit preferences to source mode, then go to a UPC wiki (wrong editor will be set up on a UPC wiki).