I agree. He's young and going through a mini-bad patch -- and of course mistakes at CB tend not to go unnoticed. For example he misjudged a sliding clearance on Sunday, in difficult conditions, and scored an own goal. He made the right decision in going for that clearance, as it could have turned into something close to a tap-in for Gabiaddini (I think), but the execution was marginally off. That's a failure in execution -- there are other examples that I can't think of right now where he's made the wrong decision, e.g. getting caught on the wrong side, but far fewer than I'd expect of a young defender in his first season here.
Also, Opposition managers/forwards wouldn't have had a plan for him earlier in the season but they'll know all about him now. Which angles to run, how much worse he is on his left foot, etc.