I recently changed audio interfaces from an NI Komplete 6 to a Focusrite Sapphire 6i6. For the most part, I am very happy with the changeover except for one thing which I am not sure is attributable to the audio interface. When playing back a track with midi instruments, at least one track will end up with a stuck midi note or notes. That is, the chord or notes start playing in a particular track but when the duration of the note ends, the sound keeps going. Stop the playback and the notes still play. A midi reset stops the notes.
 
This happened very occasionally with the NI interface but happens with almost every song I play now.
 
What I need to ascertain is whether this could be a driver issue or if there is some other known reason that may cause this to happen.
 
Anyone experience anything similar?

I am aware that the problem is Note Off messages are getting lost or not read. The issue is, what is causing the problem!

This sounds like a classic case of midi buffers needing to be set.
In Sonar Platinum I find 500 to be the new norm. Go to preferences/midi and check your buffers.
 
 

If you're inserting soft synths in audio track FX bins, try using the Synth Rack instead. I have seen issues with stuck notes when synths are in FX bins. Problems with the MIDI 'Prepare Using' buffer being too low usually manifest as dropped note-ons rather than note-offs, but it's possible that could have a bearing. As Chuck said, 500ms is a good starting point for most systems/projects.
 
I'v experienced stuck notes when using MIDI FX plugins (e.g. MIDI Event Filter) as well, but more often with live input than playing back recorded MIDI.

Thank you for the advice chuckebaby and brundlefly. I have tried a range of buffers from the minimum allowable of 20 to the maximum allowable of 10000 and the notes still get stuck. The issue is not with soft synths. They all work with no issues whatsoever. I am using a Roland Sound Canvas module which runs into the 6i6. I started a new project with one midi track and recorded into that track. No issues with recording. But, when playing back, the stuck notes happen. This leads me to the conclusion that it may well be a driver issue with the 6i6 but I am not really sure. Any other clues?

I've has issues in the past with stuck notes and it's worth checking to see if the ones which are sticking have a gap, even if it's only a few ticks, between itself and the previous/next note.
 
Short version - overlapping notes can cause sticking.

Bristol_Jonesey
-checking to see if the ones which are sticking have a gap, even if it's only a few ticks, between itself and the previous/next note.
 -overlapping notes can cause sticking.

+1 to this
Over lapping notes will cancel out the next note.
I clean this up using Quantize but there may even be a CAL script out there, not sure. 
 
And also to Brundlfly's suggestion. He brings up a good point as well that I did realize.

has this bug been reported via the official channels?

Er, do we know for sure that what the OP has posted is a bug?

dunno, but i think "overlapping notes can cause sticking" (notes) counts as a bug?