I dont know it this is a known issue.
I've found animation glitches while I was working with sequences.
So I've set up a test project for investigate the problem.
It seems to me that if you use sequences having different fps than game's fps, glitch happen except the first time.
I've attached here the test project to show you the problem.
As simple workaround, if you need sequences having lower fps than game, use the same fps of game but duplicate each frame into sequences.
It's not very flexible but it works.
Workaround test too is in the attached zip.
Zoiba