This issue is pressent on all the different Mac models running Monterey we have in our offices.
We used an Ellisys sniffer to check the air traffic and found that macOS does not continue with the pairing after the pincode has been entered, both for Classic and Secure Connection pairing.
The result is that there is no way to pair with Ble devices that uses PIN code pairing method. Other pairing methods seem to work.
All the devices that were paired before updating to Monterey work perfectly until you remove the pairing and then is impossible to pair again due to the mentioned issue.
To trigger the pairing, we used our own application and also third party ones with exactly the same result.
We tried macOS 12.1 beta1 & beta2, and the issue persists.
Any advise?