I have a DNN installation (version 9.11.2). After upgrading 2sxc from 17.8 to 17.9 and later to 18.6.1, the edit mode no longer works. Instead, I immediately get an error in the logs

System.TypeInitializationException: 
  DotNetNuke.ExtensionPoints.ExtensionPointManager
---> System.TypeLoadException: 
  Could not load type ToSic.Eav.Documentation.PublicApi 
  from assembly ToSic.Eav.Core, Version=17.9.0.0

Expected behavior: The edit mode should open normally so I can edit content.

Actual behavior: The edit mode crashes right away with the error above.

What I’ve tried so far:

• Redeployed assemblies (cleared the bin folder and copied fresh DLLs).

• Checked for leftover versions of ToSic.Eav.Core.dll.

• Cleared cache and restarted the site.

Question: What causes this TypeLoadException after upgrading 2sxc, and how can I fix it so that edit mode works again?