I have the same exact problem with sample rates except mine is only affected when using LOGIC PRO. It takes my pro recordings at 44.1 and 48k and states "Sample rate not compatible" and thinks it's 6k sample rate.
If I use "preview" (QuickLook) it plays my files fine, but if we run the audio out of LOGIC PRO via Thunderbolt -> to our ZOOM Tac-8 digital converter, the music is scrambled badly. We've tried everything but the only thing that returns the sound to normal is to go back to 10.14.4. This started with beta 1 and now even with the current beta (May 7th) it persists. If it were just Core Audio I don't think Quick Look and playing from the laptop would work, so my guess is it's something else.
If we open any other music software (Wave Editor, iTunes, etc) everything sounds fine playing via the TAC 8. For us it's just when using Logic Pro 10.4.4 and the new OS X Betas (todays is beta 5 18F131a) in combination.
Was this fixed? I'm having this issue with Catalina 15.1 on a mbp 2019