Not sure if this has been handled, or is known but this is a minor issue.
This only seems to happen during midi playback and not youtube playback but steps to reproduce would be something along these lines:
Login to hooktheory and open up a valid playable tab
Select piano radio button
Press play button (notice after pressing play, the button changes to a paused state to indicate to the user if they press this same button again, playback will be paused)
While midi playback is playing, manually change the cursor location to a different location of the tab
After clicking somewhere else in the tab during midi playback, the play/pause button should still be showing “pause” state.
After clicking somewhere else in the tab during midi playback, the play/pause button changes to play state even though the tab is still playing for the user. If the user then clicks on play state, state returns to paused state without pausing the playback. The user must press this button twice in order to pause.