Thank you!
Ok so this is what I found:
I get different behaviors, depending on what MIDI player I use (I use DOS exclusively).
GSPLAY gives me a speeding up / slowing down tempo and that hanging flute at ~33 seconds. MEGAMID has consistent tempo but also that hanging flute at ~ seconds. This is with both, MPU401AT and AWE64 Gold.
The only player that plays it correctly is MIDPAK, which uses a MPU401 driver from John Miles. This one has consistent tempo and no hanging instrument at 33s. However MIDPAK doesn't seem to have an option to change the MIDI port, so I had to briefly remove the MPU401AT from the machine and set the MPU401 of the AWE64 back to 300. Both MPU401 interfaces played the midi file perfectly.
I have attached a recording of the SC-55 connected to the AWE64Gold and played with MIDPAK.
Is it possible that this game uses the John Miles MPU401 driver?
So looking at this I conclude that this is not a hanging note bug (AFAIK the AWE64 GOLD has a perfect MPU401 interface in this regards), but some issue to do with this MIDI file and what player you use.
I'm happy to test the game, but not owning it, how large is it? If you're happy to email it to me / put it on DropBox (just for testing) with a save game of that level I'd be happy to test it for you. Because I believe that this game comes with the necessary MPU401 / MIDI driver to play it correctly 😀