Has anyone else noticed wear on the sides of their cogs from the chain rivet heads?

I noticed this the last time I cleaned my drivetrain, but I finally got around to taking a picture.



Do like how they're aligned with the troughs of the next cog down?

This is on an 11-speed Ultegra cassette which I've only used with 11-speed chains- specifically Ultegra CN-HG701 and KMC X11- so don't go suggesting I've been using the wrong chain. This is the original cassette that I built the bike up with, so it has maybe 8-10 thousand miles on it. Maybe more, I can't believe I'm only getting 3 thousand miles per chain.

I'm not worrying about it, it's just something interesting to note. Also, it's most pronounced on opposite sides of the cassette, but not noticeable 90 degrees around, where the ramps happen to be, if that has any relation to it.

It's probably not a chain line or cross chaining issue (I'm usually in the big ring), or there wouldn't be the wear on the middle cogs. There's probably no wear on the smaller ones because I'm not on those as much.

No, I'm not going to see if a chain with lower profile rivets (such as a 12-speed chain) changes things.