On Microsoft Remote Desktop 10.7.6 (1972) on macOS 12.2.1 (21D62) on a MBP 16" 2021 M1 Max.
Using a Dell U3818DW display as the only display.
I have a remote session window taking 2/3rd of the screen.
If I leave the computer for a while, when I wake the machine back up, the Connection Centre window indicates the remote session is still active. The session shows in the "Window" menu too.
However, clicking on either does not bring the session window up.
There are no messages about losing connection
Only workaround seems to be to disconnect session from Connection Centre and reconnect.
Seems like a bug to me.