Bug with looping animation?

ralph.loop("walk", fromFrame = 20)

I expected this code to make Ralph loop ‘walk’ animation from the 20th frame, and and after the end of animation is reached, the next loop starts at 0 frame. But any further loop always starts from 20th, so the animation is bound between 20th and the last frame! Is it a bug or I missed something?

No, the fromFrame and toFrame parameters of Actor.loop() constrain the range of the loop, not the starting frame. If you want ralph to loop over his entire animation range, starting from frame 20, use this:

ralph.pose("walk", 20)
ralph.loop("walk", restart = 0)