Bluetooth - Paired but can't connect

[daveozzz]

Having this same problem connecting to 7.3.0.
Android (Mi A2 - jasmine_sprout - android 10) will pair to Moode Bluetooth but the device only stays in the "Currently Connected" list for a couple of seconds and drops off.
If I try to Connect again, nothing happens - seems to just ignore the request.
I've tried removing the devices so neither know of the other, rebooting both, and repeating the pairing process but it always falls at the same hurdle.