I am doing volunteer tech support for Linux users of War for the Overworld and
I've had a couple radeon users report problems with the game being rendered
very dark ( https://forum.subterraneangames.com/attachments/menu2-png.2894/ ):
https://forum.subterraneangames.com/threads/ingame-colors-to-dark-to-play.4941/

When I replay their apitrace on my own machine (nVidia card) I do not see such
issues, and have not had reports from any non-radeon users, so I suspect that
something is being done incorrectly in the driver.  I'm happy to work as an
intermediary for these users in order to collect more information and would
happily provide a link to user apitraces if that would help.