The “note offs” should work with up to date firmware and software. The other thing that works is creating a choke group. A Choke group iks a set of midi notes that are limited to allow only a certain number to play at one time. The number playing at one time is called “polyphony”. With a bass, you generally only want one note at time. Of course, there are exceptions to that. When you set up a collection of bass notes, give the set of notes a Choke Group number that is not being used. In the example above at post 6, the Choke Group was #2. The polyphony was set to 1. That means that among the notes in Group 2, only 1 can play at a time. This, by itself, would not cause a note to cut itself off, if it were the last note of a song, or the last note before a long rest, etc. Therefore, if you run into issues, the process used by Guitar Stu would solve the problem, as that velocity 1 note would stop the playing of the prior louder note.