At the moment your proficiency being excluded from difficulty in advance instead of added to the die roll. People already asking Larian to reverse it as it supposed to be with proficiency bonus written near the die.
I guess I don't understand. Did they state a reason? What's the point of proficiency in a skill if it is not added to the roll?
No one stated anything. You still get effect from your proficiency. They just got the formula reversed:
Success if x>y-z
Instead of
Success if x+z>y
Mathematically it's all the same. Cosmetically it's confusing, yes.