Is The Afb On The Br187 Broken?

So I've been having an issue in tsw3 that I've never had in tsw2 for a while now, only really decided to ask for help now after i redownloaded the game. Basically, as soon as I turn on the AFB on the br187, the brake pressure locks itself permanently. I've genuinely struggled to understand why, is it something I'm doing wrong? I do everything like I did in tsw2 and yet it stil doesn't work.
To summarise it,

AFB off
brake pressure at BP 5.1
brake pressure at BC 0.0

ABF is activated
brake pressure at BP 5.1
brake pressure at BC 3.3

Attempt to give power with AFB active, doesn't release the pressure.

Any attempt to turn off the AFB
brake pressure at BP 4.0-5.0
brake pressure at BC 1.0-2.0
And from then on the BC pressure is permanently stuck no matter what I do.
Idk what to do anymore, this one of my favourite locomotives and I'd hate to stop driving it.

 

Hi, I made a short video for you, it seems to work OK for me. It keeps the brakes on until it gets to about 5 kmh.I hope it helps.

 

If i stop and set AFB off, the brakes will not release.
BR 187
TSW4