FYI as i just noticed it happens on the first and secondary screen with the known error:
May 23 14:16:23 HOSTNAME kernel: [18314.479875] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun ** Summary changed: - [Thinkpad T450s] Screen flickering on second monitor with docking station + [Thinkpad T450s] Screen flickering on external monitors with docking station -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-intel in Ubuntu. https://bugs.launchpad.net/bugs/1572667 Title: [Thinkpad T450s] Screen flickering on external monitors with docking station To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1572667/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp