I've tried changing the below advanced MIDI settings and the issue still persists
MIDI monitor in the DAW shows no activity after stopping the DAW, however notes on certain synths (in my case, a Roland D-50) hang until I turn them off
Note Chase and Cut
In the Studio One/Options/Advanced/MIDI (macOS: Preferences/Advanced/MIDI) menu, you can find two options: Chase Long Notes and Cut Long Notes at Part End.
Chase Long Notes should be engaged if you would like Studio One to play back a long note even if playback begins after that note's Note On position, effectively treating the playback position as the Note On. This is very useful when working with long, synthetic drone parts, for instance, which may have a Note On at bar 1 and then continue throughout the rest of the Song.
Cut Long Notes at Part End should be engaged if you would like a note to stop playback if the related Instrument Part ends before that note's Note Off position