Hmm ok. My experience with Lithium batteries is with EVs. Do you have a low discharge rate on your pack? Because the EV battery pack needed balancing like every charge. Otherwise it has to be a quality difference.
Most EVs don't use LiFePO4 although some are moving to it. There are also hundreds or thousands of small cells in most EV packs. With that volume you'll get more variation between the best and worst cells. You also need it to be foolproof and require no maintenance.
My average discharge rate is much lower than 1C which does help. The max is around 0.9C but that is pretty uncommon.
