Sometimes when loose fur releases in an area of dry skin flakes can come out with it. I’ve seen this with Wick. If you find it’s sourced from the same spot, examine that spot. For example, Wick developed a small scab a few weeks after a shot I gave him and it kept shedding skin as the fur grew in and skin repaired itself.

It looks pretty negligible so maybe just monitor to see if it gets worse or other health behaviors change.

I agree with Wick. The differential would be fur mites (cheyletiella mites). If it is fur mites it can sometimes “heal” on its own (the rabbit’s immune defense manages to fight it off). If it doesn’t heal of itself, you’ll start to see more dandruff-like flakes and also spotwise hair loss where the dandruff originates from. Sometimes you can feel scabs like small callused spots, but when you look there is no sore, just a white-yellowish crust.

Fur mites are best treated with selamectin or ivermectin. You do a repeat treatment after a couple of weeks. You can brush him to help him get rid of as much of the skinflakes as possible.

Fur mites are very, very common in buns that have had some stress on their system. Kurotta has, as you’ve told us, recently had that.

Hopefully this is just dry skin though. You should watch it, I know you will, of course.