Title: Key-Repeat Not Turned-Off On Keyboard Just Plugged-In
When you plug-in a USB keyboard after the application is initialized, if you hold down a note key (or the Play-Key for chords) longer than a half-second, you get a distorted sound. The distorted sound is the result of automatic key-repeat happening.
Cause Of Problem:
The application turns-off key-repeat when it initializes. If a keyboard is plugged-in after initialization, key-repeat on that keyboard is (by default) turned-on, and the application has no indication that a keyboard has been plugged-in, so it can't turn-off key-repeat for the new keyboard.
Make sure any keyboard(s) to be used are plugged-in before initializing the application.
If it happens due to oversight of this need, simply hit the “Num Lock” key of the numeric keypad once (or twice), and the problem will go away.
There is no fix for this. Linux is doing what it should, and the application receives no indication of a new keyboard being plugged-in, so it can't take action.