Cracks ans pops / dac+dsp / 20201213 hifiberryos

Describe the bug

1. two loud crack on startup / with DSP-V10 NO CRACKS
2. loud pop on stop playing / only if Spdif is active and newer played / same behaviour with DSP-V10

HiFiBerryOS version
20201213 “DAC+ DSP Universal Version 12”

HiFiBerry sound card
DAC+DSP

Raspberry PI 4

Expected behaviour
No cracks and pops