This is on Intel I guess? Your investigations into bug 1580792 does point out that the driver complains of a bad argument to glCopyTexSubImage - the only consumer of glCopyTexSubImage that I can find is in the Qt's font rendering system - so if it fails, it would cause font rendering issues. That's my best guess currently
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to unity8 in Ubuntu. https://bugs.launchpad.net/bugs/1583088 Title: Randomly corrupt characters in text rendering, mainly in Unity8 window titlebars Status in qtmir package in Ubuntu: New Status in unity8 package in Ubuntu: New Bug description: Corrupted characters in text rendering, mainly in Unity8 window titlebars. I think this is a new issue. It only started happening (on xenial desktop) in the past month or two. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qtmir/+bug/1583088/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp