Crown seems to be filed down on series 2000

I've seen this on more than a few older watches, mostly on the 2000 series. The crown is gouged or filed down. Anybody know what causes this? I doubt anyone would intentionally file it. Could this happen from contact with the skin, over many years? The pic is from an ebay auction but I have a 2000 series watch with the same gouge. Strange.

Caught it when polishing the watch?

In my experience, it's simply down to catching the crown on something and the wear marks are likely worn down over time .If the watch is worn on the left wrist, the crown would probably be first point of contact if you were to swipe the corner of a wall for example. It's also possible that it's down to damage from tools, again with the damage being worn smoother over time.