The monophonic emulations appear to lose notes. Probable cause is any release just after a new note is pressed and this is applied to the new note rather than finding a match? Need to review the note_off selection for single voice emulations.
The fix to the note logic was actually easy but it brings up a few other points that may also need an enhancement.
The original monophonic logic used highest order or lowest order note would be the one that sounded and that playing legato style would move the note with or without another key-on event. Also, it gave some interesting playing styles where releasing a note would take the next one up/down (apparently with/without key-on events again however I would debate that capability without onboard CPU which few had).
None of that is emulated in Bristol. It could be but would require an ordered stack of notes to be built up and operated on when in monophonic mode. That is not a fix, its an enhancement and may be delayed until I have some time or somebody (reasonably) complains about it.
The forum now contain a request for corrected monophonic note logic. We may have to look at some form of ordered note stack and rework the note_off signaling from the engine to the midi handlers (key_done suppression).
This needs to be closed. The note logic is now fixed in as much as it works as designed. Any requirement for monophonic legato style needs to be taken up as an enhancement request.
Feature request 2528893 has been opened to implement an alternative monophonic note logic.