Cue Points Issue

So... this is a first... while listening to playback, usually I just press the letter "C" and the cue points magically appear in the timeline. This time around, however, when I pressed the letter "C," the playback paused. So I openened a new Storyline file to create an "example issue" story, and the cue points worked just fine. When I went back to my original story file that was having the issue, suddenly the issue had repaired itself and the cue points were able to appear again, without pausing playback.

Any ideas why this happened??? Just wondering if you've heard of this before, in case it happens again. Thanks!