Encountered this bug earlier, the rogue ability crippling strike has become permanently bugged.
Cant activate it as it says "already activated"
I did a quick search and found 3 separate threads reporting this bug back in Aug/Sep 2014. Pretty disappointed to see this bug still present.
http://forums.obsidian.net/topic/68451-v278-per-encounter-abilities-locked-out-of-combat/
https://forums.obsidian.net/topic/67631-crippling-strike-doesnt-work-anymore/
http://forums.obsidian.net/topic/68019-rogues-crippling-blow-ability-suddenly-behaves-as-if-modal-and-stuck/
Does anyone have a fix for this, i didn't notice it right away and had already played on too far to be bothered going back and starting a new game.
It's not game breaking, but i would expect to be able to use my abilities. I've managed 4 levels without it so guess I will press on.
