Version 10.0.73 on OSX 15.6 (M4) generates audio when it is stopped!

[u!Z7]

There is a very low volume infinite delay or reverb sound still playing after Mulab is stopped. Bug or by design?

[MuTools]

Too few details.
Best to share a little project, as little = narrowed down as possible, and without any VST/CLAP plugins, that repeats the issue you encounter. Then zip it and attach it here in your reply. Then it can be researched. If the issue you encounter is related to a specific VST/CLAP plugin, replace it by another similar VST/CLAP plugin from another developer, and check whether the issue persists. If yes, then try to replace it with a similar MUX preset (eg. MuVerb), check whether the issue persists.

[u!Z7]

project zip attached; no external plugins used

[u!Z7]

I think I found it - when feedback gain of the modular feedback delay of the BP Delay is raised above certain db it goes into a periodic feedback loop. (User error)

[MuTools]

Good that you found the reason