Is this a bug?

First bar, top voice should sustain but the second voice with the staccato dot is cutting off the duration of the long note. I would suppose this shouldn’t happen?

Are both voices assigned to the same instrument/MIDI slot? If so, the “note off” instruction to the lower voice will affect both voices.

Try using IRV in Play mode to assign the two voices to two different instruments or two instances of the same instrument so MIDI messages affect each voice separately.

Thanks Derrek, Will try that.