Thanks for clariffying USB vs 5 pin midi. I am still getting a lot of Bluetooth dropout. This never seemed to be the case prior to Contol 3.7. What i've noticed is, and i've tried this with two Macs now, is that the 'Bluetooth Paired' light no longer comes on. It's the same with a Mojave Mac Pro and a Catalina Macbook. This seems to be a recent development with the Mac version of the latest Control app.
My Mac is on Mojave and it works fine with my H9. I'd like to know more about how the MIDI device messed up the communication.
Could you try resetting your H9's Bluetooth (XYZ buttons) and resetting your Mac's bluetooth (https://www.macrumors.com/how-to/reset-mac-bluetooth-module/, reset the module and forget all devices), and pair with your H9 in H9 Control again and see if it works?
