Why does GarageBand play a continuous sound, requiring a reboot of Garage band on my MacBook Pro?

Sometimes "twice so far" when I play keyboards, organ, etc., via the GB internal sound library using my MIDI keyboard as a controller, I get a loud non-stop note.

It's like it freezes and continuously plays that one note.

The only way to stop it that I know of is to quit GarageBand and restart.

I don't think it will even let you change the sounds at that point.

Anyone else having a similar problem?

Any help would be greatly appreciated.

Thank you