//Total spitballing guess//
The earlier runs of the tanks had some design flaws / manufacturing errors that hadn't been ironed out yet and he was able to a mixture of capitalize on that and take credit for tanks that just... broke down and were either abandoned or scuttled (or whatever the land version of that is) to keep them from falling into the enemy's hands.
I mentioned because I've heard it discussed other contexts that this is something that does legit lead to misconceptions about a weapon's system (and surely this broad concept can apply to other things as well) effectiveness.
You design a new weapons system. A tank or plane or ship, something complicated. Sure if you're a halfway competent military you're gonna put it through its paces in drills and tests but sooner or later you've actually got to the put the thing in combat and you cannot account for all combat variables; operator stress and operational tempo if nothing else.
So you field a new weapons system in combat in relatively large number... it's not unreasonable to think you're gonna lose a few to mechanical and operator error just by pure random chance.
A plane or tank or ship two years into the war where all the design and manufacturing kinks have been ironed out and the operators are now operating on second nature is going to be a different, perhaps radically, different beast then the first fielded production run.
