Hifiberry DAC+ADC Pro - weird problem

I’ve integrated my new Hifiberry DAC+ADC Pro with the command:

dtoverlay=hifiberry-dacplusadcpro

Now when I select the ADC as an input with my turntable connected and playing, for like 3 seconds the music comes through, then the sound quickly gets more and more distorted before it dies out completely after ~10sec. Why is that and how can I fix this?

The HAT is mounted onto an Allo USBridge Sinature streaming transport which is connected to a miniDSP 2x4 HD used as a DAC.