These mechanism are so fussy about how they go back in again. What would help the most is if we could see what you’re actually looking at. I would want to see all the bits: the back side of the keycap, the scissor, and the actual mounting point on your Mac’s keyboard.
As much as I think it’s wasteful, there’s a solid reason why Apple mandates that anytime a keycap is removed during the course of service, it is replaced with a new one. Because it removes the factor of the old key cap. And they are so easily damaged once they’re loose. Or put back in improperly.
My money is on something bent on the keycap itself, but that’s just my wild conjecture.