Metal shaving from shutter box of A7iii?

I have had the same on my old a7 III before I sold it off.

The reason I sold it, was partly because of the feature envy to the a7r IV, partly due to more and more broken shutter issues were appearing in the facebook groups centered around that camera.

It seems that Sony saved a bit on that camera's shutter. The shutter life is rated for appr. 200,000 releases. However the amount of shutter failures seemed quite odd to me. Some only had like 15K to 30K actuations before the shutter failed.

When I sold my camera, the shutter was working fine, but I saw the same abrasions that you had, which I do not have on my newer cam. You could try to contact Sony about it, but I am not very positive they would exchange the shutter (costs around $300) if there was no failure yet.

What likely will happen, is that the serration of the edge will get worse until the shutter will catch on one of these edges and then rip apart.