Ok, I did some testing.
I downloaded the app (I never had it on my phone before)
Turned on bluetooth, started the app and started the sensors one by one. Everything OK.
Next I confugured a kit: Hihat, hihat pedal, snare.
It, again, asked for left/right hand when trying to configure the pedal…
I tried to configure kits several times. Always the hihat pedal asks for left/right hand and sometimes I get the error message after trying the pedal.
The app reacts slightly different on phone and ipad. Maybe because of different IOS versions. The phone has 10.3, the iPad 12.1.1 (Apple won’t let me upgrade the iPhone 5C anymore). For instance, the pedal lights up after configuration on the phone, not on the iPad (although it sometimes moves and always makes sound when I use the sensor).
Is it normal that the app already produces sounds when I hit with the sensors BEFORE configuration ?