Two bugs with "Walk in Shadows":
1) It says duration is 2 turns and cooldown 3 turns. I used it out of combat and my character remained invisible as long as the cooldown ticked. So either the duration is 3 turns or the cooldown only 2 turns. Didn't test it during combat.
2) I had a black (drow like) character. After using the skill and becoming visible again only my face was still that dark. The rest of the body of my character was in the default skin tone.