Object is changing state based on timeline rather than its trigger

I have four shapes that start as "normal" and are supposed to change to "hidden" on click of each shape. If you click through them quickly, the triggers work fine, but if you are going slowly (which a learner would be, as they reveal information beneath), all of the shapes change to "hidden" at the end of the timeline. There are no variables on the slide. I've never run into this before - right now I've just made the timeline extremely long, but I just can't figure out why it's happening in the first place!