additional note concerning this issue:
if you hit STOP before NOTEOFF while in overdub mode, REAPER believes your note is infinite. it will continue for as long as you extend the midi item. desired behavior would be for a noteoff to be inserted at moment of STOP in the event that a NOTEOFF was not received beforehand.
likewise, if you have a note in an item and then overdub the same note, you'd better be sure to release this note before the NOTEON of the next --- otherwise you're stuck with a trailing infinite duration note as described elsewhere in this thread.
