Comment 50 for bug 1246981

Same issue with Ubuntu 20.04(Lenovo x1 carbon gen8, logitech m350, k375s).
But it was workaround for me:
1.open /var/lib/bluetooth/<adapter_mac>/<device_mac>/info, remove the following lines, and restart bluetooth.service:

[IdentityResolvingKey]
Key=...

found in this discussion:
https://bbs.archlinux.org/viewtopic.php?id=259954