Bluetooth: 10.1 Transport mode always reports 0 for Storage

I'm trying to read the active storage medium of a Blackmagic Pocket 4K.
Via Bluetooth for
10.1 Transport mode ( https://documents.blackmagicdesign.com/ ... ontrol.pdf )
I always get
[3] = slot 1 storage medium | 0=CFast card, 1=SD card, 2=SSD Recorder

No matter what I select in the camera. "SD", "Fullest Card", "CFast",
it always reports 0.
I did check the raw byte values and indeed the camera reports a 0 here.

I just got myself a small, used CFast -card to see if this still reports 0=CFast if a both slots are occupied (CFast+SD or CFast+USB3).