What you suggested is what I normally do too.
The bug is easy to produce. Just create a new fla, add a textfield, a movie clip onto the stage. In the movie clip code add the onRollOver, onRelease, onPress ... functions. Test it: Highlight the text in the text box, click the mc multiple times. Everything works fine.
Now, add a compiled clip, scrollpane, to your library (you don't even need to add an instance onto stage). Test it: Highlight the text in the text box, click the mc multiple times without moving your mouse. You will see some onPress/onRelease events are not dispatched every time. Instead, sometimes, onRollover/onRollout events were dispatched in place of onPress/onRelease.
I'm attaching the above test fla with trace statements in the event functions. You can see what I mean.