I'm running Ubuntu 21.10 and have two identical monitors attached to my AMD 5700G system as "joined displays".
When the monitors wake from sleep or are powered back on, it appears that Ubuntu doesn't realize that both monitors are coming back. Some apps that were located on one monitor are moved to the other monitor. Which app window moves is not consistent, but at least one app will do this almost every time the monitor comes back.
I suspect what's happening is that the two monitors are not woken simultaneously, so Ubuntu thinks that only one monitor has come back and tries to move all windows to it. Or something like that.
I have other similar problems. Sometimes the left and right monitors will swap. Sometimes the right monitor will not wake up, and I need to power it off and back on again.
Is there any way I can "lock" the monitor orientation and disable Ubuntu's attempts to detect them dynamically?