@Antonio > The 3rd video is private so I can't view that one, but the first two videos show the same track "Cinematic Behaviour" loaded each time you have a problem. I'm willing to bet that you have damaged MP3s causing this issue. Please use one of the following tools to repair your files:
One of the best utilities for detecting and correcting errors in your MP3s.
MP3 Scan+Repair (Free)
This is the best (and one of the only) MP3 validators for the Mac. Does a fantastic job and it tells you what's wrong!
After you have scanned your files, I suggest you format your export drive (do it TWICE, do NOT use the built-in Windows formatting utility if you are on Windows), then re-export your files to the USB and try again.