Apple Watch Series 10 - Black Housing Material peels off

Hi,

recently I was cleaning my watch and noticed two dots on the inside besides the glas sensor. I used my finger nail to remove two 'pimples' stuck on the housing, which now show bare aluminium. I think this was no dirt, the pimples were the coating of the aluminium. Is this supposed to happen at some point in life of the apple watch? I expected this to be an eloxide not a coating.

The shiny dots in the picture is no dirt on the watch, its a hole in the black sort of coating, that exposes the bare aluminium.

Has anybody experience with this?