I know from your past efforts that you have become a first rate pizza maker, and I can tell from just the way you recite things that you are on top of your pizza game, so I'm inclined to think that what you experienced with your most recent pizzas was just a fluke. I do have a few thoughts on this however.
Looking at your recipe generally, it is in proper balance for a Lehmann NY style dough. And your technique as you described it seems fine. I will mention, however, that recently I have been experimenting with just using the stir/1 speed only--for the entire mixing/kneading process, except for an occasional use of the #2 speed for less than a minute at the end of the kneading process for good measure. The total knead time may be longer because of the slower knead, and while I keep my eye on the total knead time, I look more for the final condition of the dough that I am trying to achieve rather than the total elapsed knead time. With my machine, I am constantly starting and stopping it to make adjustments anyway, so trying to time the entire process exactly becomes somewhat meaningless--even if I were to use a stopwatch to tally total elapsed time (which would be even more meaningless).
You used the term "bready" to describe the finished crust. When I think of "bready", I think of a tight crumb as opposed to an open an airy one. A tight crumb often results from a lot of kneading--either a knead over a long time period or at a high mixer speed, or both. If your crust was "bready" in the sense as I think of it, then you might try shortening your knead time at the #3 speed or using a lower speed. I tend not to think that your kneading process was at fault since you indicated that the techniques you have been using to make the Lehmann dough have produced consistently good results in the past.
So, if I were to try to find a villain in your scenario, I would be inclined to point my finger at the dough temperature. If your dough was cold and partially frozen and you gave it only 1 hour of counter time to warm up before shaping, dressing and baking, it's quite possible that the dough wasn't quite ready for prime time. Freezing itself does damage to the yeast by killing some of the yeast cells and it obviously slows down the undamaged cells and retards the normal fermentation rate and process. You didn't indicate whether the dough at the time of shaping was soft, slack or gummy or without a good "feel" to it (due to the release of glutathione), but if any of these conditions were present, then they could have accounted for the reduced oven spring and final character of the crust you achieved. It's possible also that the dough was just too cold, although you didn't indicate any problem with bubbling in the crust. BTW, when I put a dough on the counter to warm up, I have been using dough temperature rather than time to determine when to start shaping the dough. This takes room temperature out of the equation entirely and means not having to make adjustments to the counter warm-up time because it is summer or winter or whatever. I just stick an instant read thermometer into the dough during its counter rise and use 62-65 degrees F as the target temperature.
FYI, I don't think your IDY yeast was at fault. I have IDY in my freezer that has been there for years and have never had a problem with it. I might add a teeny bit more to recipes to compensate for its geriatric condition, but that's about it.
Please let us know if you determine the cause of the problem with your most recent dough. The answer might help others at the forum.