Mac Catalyst: AUv3 Extension no longer works on MacOS, still works on iOS

I have a Catalyst app ('container') which hosts an embedded AUv3 Audio Unit extension ('plugin'). This used to work for years and has worked with this project until a few days ago.

  • it still works on iOS as expected
  • on MacOS the extension is never registered/installed and won't load
  • extension won't show up with AUVal
  • seems to have stopped working with the 26.1 XCode update
  • I'm fairly certain the problem is not code related (i.e. likely build settings, project settings, entitlements, signing, etc.)
  • I have compared all settings with another still-working project and can't find any meaningful difference

(I can't request code-level support because even the minimal thing vastly exceeds the 250 lines of code limit.)

How can I debug the issue? I literally don't know where to start to fix this problem, short of rebuilding the entire thing and hope that it magically starts working again.

Mac Catalyst: AUv3 Extension no longer works on MacOS, still works on iOS
 
 
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