I'm inclined to not call it a bug, but...
1. Create an actor.
2. Assign an amination.
3. Tint the animation with r g and b in script.
4. Use draw_from to transfer the actors current frame to a canvas actor.
Result: the canvas uses the true colors of the actor rather than the shaded ones. While that is the logical result, I am not sure that it would be the expected one.
A minor issue. Nothing I cannot work around.