Same issue here for months, same two monitors or mostly after other monitors connected, eg TV in mtg room. Sometime just turning monitors on/off or unplugging/plugin the cable again. Also in 11.4 :-(
sftroels
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
From
Danmark