Check out the bug reports thread, I’m seeing some similar reports of missing note off messages with similar conditions.
A midi monitor can be downloaded free to your computer and it would confirm what is being sent.
Read the end of this post below where he says “edit 1” and then use the search feature within that topic using the keyword “note off” and see if anything else looks similar to your issue so you can report it if necessary.
I’m not sure what else to suggest at this point but confirming the issue with a midi monitor would be a good start.