Not just on SKW, Ive noticed this on the BR187 on SKA (in fact any service with the 187) drags its breaks under AFB at low speed.
Interesting observation. Have not actually noticed it until you have pointed it out. For me, however, I do not see 0,1 BC pressure, like on your videos. I do see the pressure going up, slightly, though. BP, like in your case, seems to drop to 4,9, at occasions. Not always visible, though.
