It's interesting you say the problem does not happen in Wayland sessions. Your logs suggest the kernel is having trouble, which then confuses Xorg:
Oct 23 08:32:51 jik-d42-x1 kernel: i915 0000:00:02.0: HDMI-A-1: EDID is invalid: Oct 23 08:32:51 jik-d42-x1 kernel: [00] BAD 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 ... and Oct 23 08:32:52 jik-d42-x1 kernel: [drm:drm_dp_dual_mode_detect [drm_kms_helper]] *ERROR* Unexpected DP dual mode adaptor ID 54 The problem "EDID is invalid" means it is either a kernel bug, a faulty monitor or a faulty connection. Please try a different HDMI cable to see if that helps. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1849484 Title: [X1 Carbon 7, i915, HDMI] Ultra-wide monitor recognized properly when plugged in only intermittently [Xorg only] To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1849484/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs