in that case you can also try to format the drive on NTFS to see if the same happens. If yes then i would recommend contacting the manufacturer of the card radio to see which drives are recommended for it.
also you can see if the same happens with all the filetypes you store inside the flash drive.
The problem is that everytime i include a new folder on my PC it apperars duplicated on the car device.
Check the drive in another pc, or two, to see if the duplicates show there also. If not then the problem is the car’ stereo system. Check it’s manual for specs on drive size, drive format, file types.
I have checked it in other PC´s, the new folders doesn´t appear duplicated. I can´t try to format it to NFTS because the car stereo system doesn´t accept it.
The only solution i found is to modify the name of the pen, then everything appears correctly, but it doesn´t seem to be a usefull solution…