Hi Bachu,
Have you found a solution to your problem? I have the same issue at the moment with my x-t30ii.
But I found out, that when you set the Aperture to A (auto) (e.g. at the lens) and the shutter speed to user-selected. Then you can rotate the front command dial (the wheel in the front of the camera) (if its set to F (Aperture)) all the way up, then the mode changes to S (Shutter Priority).
Now leave the mode in S and only change the shutter speed to A (auto) and now the mode changes to P.
Hope this helps.