What is this in micrograph?

I collected about 4000 micrographs yesterday. But while I’m processing it, I found out there are many strange things in micrographs. I think that are ice contamination. But that’s too many to consider ice contamination. About 90% micrographs, that strange things are there. So, what is this ? Even, another grids which another co-worker independently prepared are the same.

This is surface contamination, probably deposited while the grid is in the scope - maybe an issue with the vacuum or thermal contact with grid?

Thank you for your reply. You mean that microscope maybe defective, right ?

Not “defective”, just that the vacuum wasn’t hard enough, or contact between the grid and the holder is not great. Was the grid in an autoloader or a side-entry holder?

They were in autoholder.

Thermo Fisher Scientific or JEOL scope? Is the grid warped or distorted (which may cause poor contact) at all if you check after mounting?

Thermo scope. I think that it was induced by thermal contact.
In the process of transfering grids from buttons to loader catridge, I was very urgent and there were some mistakes.
Thank you for your suggestions.