I legit had this same question today, while testing the Canoness' debuff. It does seem to work. A unit's evasion went negative, and some units seemed to have an improved hit chance. Need to do more to confirm, but it seems to let you counter things like cover.

Love it, had fun playing Aeldari. One suggestion for next patch. Increase Autarch move rate. 3 is lower than any Eldar infantry, and it's a jump pack unit. Made a full post on the subject under suggestions

This one is pretty simple (the irony of my long-winded post is not lost on me). I've just finished playing my first Aeldari campaign and I found the Autarch's movement rate to be what I can only assume is mistakenly low. With move of only 3, it is one less than any Eldar infantry (except wraith blad...