I saw it a little differently, though I admit there were frustratingly many plays just as you described. But I think it’s solely down to his technique. He’s a tall guy and when he stands up too quickly (which he does far, far too regularly), he essentially loses the play at the snap. The smaller OL gets up and under him and is in control of the rep.
But what encourages me about it is that despite “losing” the rep technically, Martin still holds his own. He rarely gets wiped out of a play, even when doubled, when 99% of DL would. The OL has won the rep but he doesn’t really win it, it’s more of a tie.
However there are also plenty of flashes of what he can be when he stays low, when he uses his length, man he absolutely annihilates some running plays from time to time. They’re just not consistent enough. I was really encouraged by his play at the Shrine Bowl especially, you could tell he’d spent a lot of time on those technical weaknesses. He had some dominant reps against some of the best college football had to offer.
He’s a ball of clay right now for sure, but I think his attitude and physical gifts were just too enticing for us to pass up.