I don't think that is a bug. It is a feature.

Hitting that button while the Transport is moving is like telling the program that you may be wishing to Record on that track. Also, a selected track has associated things with that selection, such as the Edit window for that track (may be in the background but still changes by the track) and that is locked once the Transport starts moving.

Most all sequencing softwares I've used respond much differently when the Transport is moving, whether at Playback or Record mode.

This one is likely best conquered by relearning where to click.

--Mac