After a while on my #librem5 #dogwood experiment call, I stopped fidgeting with it and the screen timed out.
The lock screen came on behind the call screen. You could see it around the edge of the call window. I couldn’t figure out how to get to any other app from that point until I ended the call.
Annoying
Most of what I’ve seen so far is already in their bugs database https://source.puri.sm/Librem5/calls/-/issues
Purism did say this thing was pre-production, so don't take this as complaining, just noting.