Sounds like this could be a side effect of the fix for bug 2051074 that you just installed. Maybe Kai-Heng Feng will have more insight.
** Tags added: multimonitor -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2060204 Title: Resolution drop on third monitor on USB C To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/2060204/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs