When connect Yamaha keyboard to iPad with ipados 15.4.1 or 15.5 beta 1 or 15.5 beta 2 the music app likes korg module pro, cubasis, Camelot Pro crashes. I tried with other midi keyboard like Arturia or Native instruments and Midi works. Reading the forum seems somethink linked with Yamaha keyboard. Until ipados 15.4 all worked fine.