I'm running Windows 10 21H1.
Since upgrading my installation of mIRC from 7.6x (don't recall the exact version, sorry) to 7.72, I've experienced hangs when connecting to my PC via Remote Desktop. When the hang occurs, mIRC is completely unresponsive and doesn't answer server pings, etc. The hangs seem to occur randomly, although thus far I haven't seen one when mIRC has had focus. I don't know if they're limited to Remote Desktop, as I don't currently have physical access to the machine.
Task Manager shows ~25% CPU usage when this happens, which corresponds to using all of one core on my machine.
I generated a core dump and can provide it privately, if that'd be helpful.