Why would some folders disappear when device (N7) connected via USB?

[AC Question]

When I connect my N7 via USB one of my favorite folders is invisible as a folder and appear only as a file that I can not open.
The folder is visible on device and I can open it and reach every doc in it. I can also navigate in it via airdroid.
The problem is specific to usb connecting.

Does someone understand why and see a solution?
Thanks!

 

[Rukbat]

It's been a while and no one's posted any response, so this is just to let you know you're not being ignored. Unless there's something special in that folder keeping it from being recognized (like no name, just a dot and an extension), I would have to have the phone and do a few experiments to even have a chance of figuring it out.