Audio while scrubbing

Adding to this thread as I have a brand new install of Premiere 25.6.4 on a brand new M4 Studio Pro. Scrubbing went dead even with the box checked in the Audio settings. Toggling the scrubbing hot key does nothing. I noticed it stopped working while trying to test the offset for external monitors in the Playback settings menu. I switched Primary Audio Device back to Adobe Desktop Audio instead of Blackmagic Playback, and suddenly the scrubbing was working again, hotkey and all. Not sure how this jives with the Audio Hardware settings, which indicate Blackmagic UltraStudio 4k Mini as the Default Output, so I'm waiting to see if further bugs pop up with these two settings are in conflict. But at least I have scrubbing back for now. 

Delete the Media Cache and Media Cache files:

https://community.adobe.com/t5/premiere-pro/faq-how-to-clear-your-media-cache-in-30-seconds-in-premiere-pro-2020/m-p/11017257/thread-id/260446?page=1

If that doesn't work, try creating a new project and import the old one into it.

Try Preferences > Audio Hardware and set Input to None.