External Effects bypass problem

Bypassing/deleting an external effect (mix bus compressor) in Cubase 12 Pro causes the session to freeze (25% Performance Meter spike) and introduces a low level noise. A brand new Cubase session does not do this. I’ve tried everything I can think of. Running M2 MacBook Pro on Ventura with RMU UFX+ at 2048 buffer. Everything is updated.
If I “soft bypass” the plugin in the Insert list, Cubase works fine but I cannot do an offline render. If I completely remove the ext hardware insert or “hard bypass” it (not sure the term), CPU spikes 25% and session falters. Session only works if I use the ext hardware compressor or I “soft bypass” it (don’t know the term). It’s not the RME. Like I mentioned, there’s no issue with a brand new Cubase project. I would very much like to render these projects offline say that I can max out some plugin oversampling. This is a very strange external effects issue.

After closer inspection, the same problem occurs in a brand new Cubase 12 Pro project. Tried resetting preferences, same problem. Weird.