I have a 1st edition iPad Pro 12.9" and I opened GarageBand. It loaded an old song automatically, and the instrument was a synth. I switched it to a Grand Piano and began to play a 3 note chord. As I played the chord a couple of times, the instrument switch back to the synth.
I tried a few more times and the same thing happened. I finally tracked it down to it performing an undo function, and I was able to select redo to change the instrument back to a Grand Piano. Every time I play a 3 note chord, it does this undo making it very hard to play what I am trying to play. It happens for any chord I play and on both sides of the screen.
I am running the beta of iPadOS as well, if that matters!
Is this normal? I've not really used GarageBand on my iPad much...