After Flame is running, sometimes an hour, sometimes 4, the undo/redo will stop working on the Gmask Tracer; then sort of trickles down to some other things. I’ll hit Undo and it’ll undo in some other part of the batch that is unrelated to the Gmask.
This type of bug has been plaguing me for quite a few software versions. I have noticed it more on my Linux box. What OS are you on?
As soon as I notice it I promise myself I will quickly do a relauch but then continue working until I make a mistake, hit undo and it jumps me into another batch and undoes some strange action from 15 mins ago. This reminds me to relaunch and then it clears up.