Published files won't show up in File Manager

Hi,

I would really appreciate some help.

We are having a problem when publishing files.

We can save versions ok but when we Publish, the files are published into shotgun and go to the right folders but they don't show up on the File Manager.

Another strange thing is that the files that don't show, have a blank thumbnail even if we created one.

This doesn't happen every time, but most of the times.

Do you have any idea where the problem cold be? Just a clue so we start looking?

See attached image.