GarageBand always sends MPE MIDI events to AudioUnit instruments

Hi,

I am developing a AudioUnit Extension (AUv3) instrument. I tested it with many AU hosts, such as AUM and AudioBus and I see that the screen keyboard sends standard MIDI messages on channel 1. GarageBand iOS works differently in that regard. When I press the keyboard notes on screen, the events are received as MPE-style events (the notes cycle through all MIDI channels). This does not work well with my app, so in my audiounit, I implemented supportsMPE like so:

-(BOOL)supportsMPE {
    return NO;
}

After I have done that, GarageBand still sends MPE-style events to my AudioUnit. This looks like a bug to me. Am I doing something wrong? How can I tell GarageBand that MIDI events should not use MPE?

Thanks,

Mathieu