Something happened here??
There was a message posted about using a Filter, but now it's gone!
A filter may be helpful, although this is not an answer as to where the problem is coming from, but it's a possible fix?
I've got a Filter prog, but it's an old DOS prog that will not work with later WinDoze systems, also it's not 'real-time' to work WHILE you're playing. It works by reading a midi file, manipulating the data as it comes through, and putting the output to a new version of the file. It can do various changes, one of which is to remove all instances of specified things, such as Controllers. It can remove ALL controllers, or remove a specific one, such as Controller 123 (H7B) which is the All Notes Off.
The previous message suggests there might be newer WinDoze versions, including things that might work WITH Reaper as a real-time add-in??
Geoff