Of the 3 stills, only the last one is what I would call egregious. I would even go so far as to call the first one ticky-tack, mainly because of his own positioning and the double team, but part of the problem is they're still photos. I have no idea if he just lost leverage/hand postion but was able to re-positioned his hands or even disengaged just after that photo was snapped. Some refs are going to give leeway for that, others are going to be very "by the book" and flag anything outside the shoulders. We all know football to some degree here so this might not need to be said but the truth of offensive line-play is that most lineman commit holding most plays. It's really the only way to block someone as big and athletic as their Defensive counterparts especially when they're fighting to keep your hands off them the whole play. It's a matter of keeping it within the chest pad rather than outside on the shoulders, effectively disguising it, and knowing when to disengage. I'd say it's the most subjective penalty that can be called on the football field with PI right behind it.
The good news is that in theory he can get much better at disguising it.