I've been having this issue on two different systems. These are laptops with 4K monitors running at 200% DPI scaling, which I think might be part of the "problem". The issue is that some icons appear to be rendered at one quarter of their proper size and look tiny, like DOpus has decided to display their 16×16 version instead of the 32×32 version. The issue does not appear in File Explorer.
Not something I've ever seen before, and I've been running 4K/200% for about 10 years now...
The icons ultimately come from the OS so I don't know why they would be a different size sometimes, unless something is interfering with things or the per-process icon cache is being corrupted.
For example, an icon-replacement tool, or Windows compatibility settings being turned on (they should all be off), could cause problems.
It's also possible something keeps generating events saying the filetype icon has been changed, maybe before the icon/registry data is fully there (or as it's being re-written again).
If you've already checked the compatibility/DPI settings, clearing the icon cache is worth a try, as a quick thing:
