Looks like the Pisound you’re using is running firmware 1.01 - you should upgrade to 1.03.
If anyone wonders, you can check your Pisound firmware version by running:
cat /sys/kernel/pisound/version
The steps to upgrade the firmware are here:
However, as this hasn’t been needed in a very long time, the scripts are very likely not compatible with bookworm or the Pi 5.
Do you have an option to do the Pisound firmware upgrade on Pi 3 or 4, running bullseye or buster Raspberry Pi OS or Patchbox OS? The scripts should work fine for them.