I am happy to report that this issue looks to have been resolved. The roll back took a bit of time to do, and I am still not sure that I did it fully correctly. However it did the trick.
I also note that there were some subsequent updates to both the Mesa libraries, and xserver-xorg-video-amdgpu driver, amongst which was a fix. Thank you, Sebastien, for all your help. it is very much appreciated. Many thanks, Mark. -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1926009 Title: Incomplete display of text To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1926009/+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