Critical / Counter penalties not applying?

I was playing a low-level polearm character yesterday. Low enough that when using the +5, -25, -25 stance my critical and counter chances were reduced to zero.

But I still got off several critical attacks, and several counter-attacks.

I couldn't make sense of this - is this in line with everyone else's experience? My stats were properly displayed in my character sheet - but I absolutely was still getting both events.

 

There is a floor value, I think it's 2 or 3 points.