I have a timeline of 10 frame labels, each label has a movieclip on it and in those movieclips there's a short animation, with a couple of actions being fired along the sub-timeline which play some sounds. I have a next and prev button on my main timeline to go between the labels. Something new seems to be happening when I use gotoAndPlay to go backards through the frame labels though. If I go from say label 4 to label 3, all of the actions on the timeline of the movieclip on label 3 fire instantly in reverse order, as if the movieclip animation is being reversed to get to its first frame, rather than jumping there instantly. This means it tries to play all the sounds, which I can see it logging in the console, before it then reaches the first frame, and then starts normally.
This appears to be happening in animate 20 and 21.