Audio interface disconnects in iOS 15

I use my iPad Pro for recording my electric guitar with an IK Multimedia iRigHD audio interface that`s connected via a Hyperdrive USB-C hub. After updating to iOS 15 I can´t get any output sound from my guitar. Everytime I connect an audiocable or headphones to the 3,5 mm jack in the USB-C Hub, the iRigHD disconnects from the hub. I use garageband and Amplitube as recording software. Everything worked just fine in iOS 14. The iRigHD works fine with my ipad and USB-C hub as long as I´m not trying to output the sound to external speakers or headphones.

I have tested several audiocables and headphones with no luck.

do anyone have an idea what to do to solve it?