Bluetooth is not working (maybe reconnecting ...)
Solution 1:
Reset PRAM/NVRAM after updating to Catalina so that any old data should be removed from the cache.
- Shut down your Mac.
- Turn it on and immediately press and hold these four keys together: Option, Command, P, and R.
- You can release the keys after about 20 seconds, during which your Mac might appear to restart.
It will resolved your issue. This solution worked in a couple of Macbooks of my colleagues after upgrading.