Run attached program on a turboR in R800 mode (timing is tuned for R800 mode). On openMSX it sounds chopped off, on real MSX you hear a very long release. It's like the channels are turned off when the rhythm bit is enabled, in openMSX, which is apparently wrong. On the alternative FM core, it sounds better.
When removing line 91, you can even hear the drums on the real MSX, not in openMSX.
demo program, see bug report
Fixed by Wouter in revision 13175.
Confirmed to be fixed by Edwin, one of the original reporters.