Animated frames desyncing with reference footage

I am very new to adobe animate as in I literally started using it like three hours ago. So far, all I'm trying to do is rotoscope over some reference footage, but I've ran into a problem where after closing adobe animate and opeing it again, all my animated frames are out of wack with the original video. I'll attach a video of what I mean. Not sure if I've messed something up, or if this is some kind of glitch.