This is my first time trying out a mod for xcom2, true concealment sounds like a great addition to the vanilla game.
The problem I experienced was on the second mission, a hack mission.
The mission started in concealment and like I expected no timer started ticking. I slowly moved towards the device when all of a sudden I got a warning that I only had 3 turns left to complete the objective. I did not spot, or attack an enemy and all my soldiers where still in concealment.

Did I make any mistakes in activating the mod? I simply subscribed to it in the steam workshop, started the launcher and ticked the true concealment box. Did I miss anything?