What controls the appearance of file icons on the Desktop?

I am using OS Monterey. An odd thing happening is that, spontaneously, the appearance of the file icons is changing. Attaching a picture to show what I mean. I prefer the one that Treatment of Injuries, Meeting 3.key but it is changing to Treatment of Injuries Meeting 1.key appearance.

What causes that? I don't see any setting that controls it?

— Richard