Not insinuating this happened, but while spending 7 years in a Seattle ski shop, we'd often find a direct correlation between a bent buckle and the color of paint on the benches, door frames, cafeteria tables. Typically it was the toe buckle. Cause was unbuckling the buckles to relieve pressure when walking inside & they'd knock the buckle when walkng, sitting down, etc. Based upon the picture, it's clear that something hit the buckle from the underside moving upward. I'd check for nicks, scratches, paint transfer etc. That may help provide clues into how it's happening. Can't see in the pic perfectly, but it looks like the buckle was open and the long latch sticking out perpendicular to the side of the boot. This provided a long lever arm to torsionally bend the base of the buckle. I would start to think about how they were put in a boot bag, trunk of car, etc where the buckle wasn't fastened closed and in the process of 'setting them down' the buckle came in contact with something solid which pushed up on the buckle when it was sticking out. Lots of ways it could have happened.
As for repair, a good shop should be able to repair in a couple of minutes. It's either the rivet or the buckle that's bent. If it's the rivet, then it'll be a simple drill out & replace the rivet. If it's the buckle or both, then they should be able to order a new one & just replace it. Cost was always nominal. Since labor was less than 10min , we'd typically only charge for the buckle cost and often no charge unless they were a repeat offender. In this case, I'd probably drill it out, bend it back with pliers & rivet it back on. not a big deal.