So using an attack didn't turn you visible, either?
I tried this in a new game, but came out of invisibility if I attacked anyone or waited/moved for 4 turns. Of course, having a duration longer than the cooldown means you can effectively stay invisible forever.
I think the spell effect is just a placeholder, anyway (same as Inspire), so it seems Walk In Shadows isn't quite done yet.
Not quite, my invis breaks upon attack but I could stay hidden forever when the skill is activated in combat mode
