I can reproduce the bug only connecting the monitor after Ubuntu is completely started.
If I boot with the monitor already attached, it works perfectly.
I have reproduced the bug with another different monitor, but just the first time that i've tried, subsequent attempts (with xdiagnose installed and then removed) it works.
I tried again the first monitor and without xdiagnose it shows the bug, i removed the monitor and the session restart regularry, i've installed again xdiagnose, rebooted ubuntu, plugged the problematic monitor and the bug is fixed
Hello Bryce
I can reproduce the bug only connecting the monitor after Ubuntu is completely started.
If I boot with the monitor already attached, it works perfectly.
I have reproduced the bug with another different monitor, but just the first time that i've tried, subsequent attempts (with xdiagnose installed and then removed) it works.
I tried again the first monitor and without xdiagnose it shows the bug, i removed the monitor and the session restart regularry, i've installed again xdiagnose, rebooted ubuntu, plugged the problematic monitor and the bug is fixed