piano sustain turns itself off

I was recording great piano tracks/improvisations the pastor days but now i cant. I played on two channels but when I switch from one piano channel to another the sustain (which is on) mysteriously becomes disabled. And even worse, when I export the recording in audio format it is also disabled there. I'm only having this problem on my iPad because I tested it on my iPhone and it does record with sustain, but is there any fix? I already uninstalled garageband and reinstalled it and nothing, still the same.