Comment 29 for bug 1768139

Small update. I've gone back to try and see what I can learn from installing pre-built kernels:

1) for some reason when I reboot sometimes I see the grub screen in mirror mode and sometimes one monitor is blank. This issue happens whenever grub is mirrored between both monitors. It is always mirrored on cold boots.

2) I went back to older ubuntu kernel versions. (https://launchpad.net/ubuntu/bionic/+source/linux)

I can confirm that the issue persists as far back as 4.15.0-18.19.

I attempted 4.15.0-17.18, but the build files here: (https://launchpad.net/ubuntu/+source/linux/4.15.0-17.18, https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/unstable/+build/14768117) do not include linux-modules-* and linux-modules-extra-*, and when I don't install those the monitor doesn't seem to be detected and there is no modeswitch after grub.

I then went back to 4.15.0-18.17 and uninstalled linux-modules-extra-4.15.0-18.17 and found the same no monitor modeswitch problem.

I will attempt to build 4.15.0-17.18 myself and see if I can get the modules to build and properly test, but this is very slow going at this point. Please let me know if there is another way to test that doesn't involve long builds.