Steps to reproduce:

When viewing the revision history, the following console warning is logged:

[CdxPopover]: The "anchor" prop must be provided to position the CdxPopover.
at codex.umd.cjs:1
at vue.js:5
at (anonymous) @ init.js:13
at setTimeout		
at modules/ext.checkUser.userInfoCard/init.js @ init.js:3

Example: https://test.wikipedia.org/w/index.php?title=User:Ikan/HotCat.js&action=ehistory

Other information:

• Happens in both Vector and Vector 2022.
• Happens in both Firefox and Chrome.

I wonder if this might explain why the initial loading state renders too small (cut off or lacking margin?)

Might be related:

• T384725: [Epic] WE4.2.18 UserInfoCard experiment for assisting patrollers and moderators
• T391102: Update GrowthExperiments to make use of CdxPopover instead of CPopover