I also have the same problem as you
I have two timelines that can be moved alternatively for each player as in chess and the two timelines follow two different paths.
I use two tags for the two timelines one is 'black' and one is 'white' and I use them to distinguish the two timelines, and the movement along the timeline is triggered by the roll of the dice; that is I throw the die that marks 5, the placeholder must move 5 keyframes. Another roll of the dice must be new by as many keyframes as is the result of the die. And so on up to keyframe 40.
Usually after the first correct movements the placeholder instead of stopping at the defined pause continues until the end of the timeline. I tried to send part of the game to Scirra but they told me the lines of code are too many. I can not send less
If anyone has any suggestions, I think it's a timeline bug