Quad SATA hat does not detect any ssd in SATA1

I have assembled the QUAD SATA kit with a raspberry pi4B 4GB and followed the 2 youtube videos. It works fine with SSDs in slot 2-4, but do not detect any disk in slot1. It does not mention anything in dmesg about a disk if it got connected to SATA1- but it find the same disk in the other slots.
It also do not lid the LED of slot 1.
Is this for sure a hardware defect, or are here some hints to debug this ?
I used the latest 64 bit RASPI OS (2022-04-04-raspios-bullseye-arm64-lite.img.xz).