actually, I think it is partially because it's in uploads instead of help
this community actually gets complimented on it's responsiveness/helpfulness all the time
if you find you're not getting any responses even in the help section
it's usually a bug you're reporting and you can just report it to the bug tracker
I actually can't say anything too helpful at the moment, because I'm a little busy
but I will say this for you to take into consideration, and maybe it will help
the canvas takes up vram like a sprite, so if you make the canvas the size of the screen, it will be like trying to have a full screen sprite. if you have several, it will probably run on your or my machine, but not on a lot of others
also, I could be wrong because I thought I had taken care of it before, but it really seems to be working
I filled in the transparent areas of your bamboo normal map with black
I know that's not how normal maps are supposed to work
but try this :
I haven't looked in detail what the separate normal maps are for, but the far right one is still doing it, but none of the other bamboo sticks, I can't get the glitch to show up.
as for the other weird canvas issues, I'll have to have a look at those tomorrow maybe.