Have you thought about how the floor underneath might be messing with the spreader? @west.seth's right about tools bending, but an uneven subfloor could be forcing the teeth to twist.
I saw the same thing with my notched trowel from Harbor Freight. Isn't it wild how nothing seems to last anymore? Like, why do we put up with tools that bend so easy?
Seriously! I've noticed it's not just the bargain stuff anymore, even name brand tools feel flimsy. It's like they all use the same thin metal now and just charge more for the paint job. We're basically paying for the same bad product either way.