Audio plugins missing on 1st launch (closing and re-opening is the workaround)

When I open a project started in v23.0 (non-beta) in the Beta 23.2.0, I get the missing audio plugins dialog, even though they are there and enabled in the Audio Prefs. Closing and re-opeing Pr fixes it - they show up the second time (closing and re-opening the project doesn't).