If I had to guess, I'd say it's an identity crisis and loss of confidence in coaches as well as the majority of the offense.
It's clear at this point that Josh's big play ability is being held back, and he's not the one choosing to do so. For whatever reason, he has decided not to rebel against whatever Dorsey and likely also McD have been trying to instill in him to be a more stereotypical pocket passer and to essentially neutralize the wild and explosive aspect of his running ability and his hero ball play. Yes, this actually has to some degree cut down on the mistakes that would come with that sort of play, but at this point it seems like a wash in that regard, all the while we no longer have any of the upside and the positives of Josh's usual style of play.
So we've absorbed all the negative aspects of changing his game, but haven't reaped any of the benefts. If the offense and the line were totally stacked then sure, we'd be a machine on offense. Instead we are predictable and teams no longer have to spy Josh, and honestly I don't think they fear him or go into each play anymore thinking "Oh *****, he might pull off something insane here." He's been neutered and they know it.
As for confidence in the rest of the offense, it's pretty bleak. Knox is anti-clutch. Diggs can't get the ball every time. We have no true #2 receiver. It was very encouraging having such a great game with Kincaid and I hope that mentally that gives Josh the confidence to basically turn him into the #2, but still. Having two guys on your offense that you actually trust isn't enough and that is painfully obvious.
Josh will always make some mistakes, but I cannot blame him too much at the moment considering what he's been told to do and the cast of characters he is having to do it with.