mp4 files get corrupted when transfering them to ubuntu 18.04

This seems like a weird issue, so I've transfered some mp4 files to Ubuntu via FTP and some of them seem to be broken, more specifically the header, I get this message when I try to play them with VLC:

[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fa7a0c812e0] moov atom not found

also this message with ffmpeg:

moov atom not found
myfile.mp4: Invalid data found when processing input

This is not the weird part since the FTP transfer itself could corrupt the files, so I troubleshooted and transferred different files via USB and it happened again, no movement from the flashdrive, no interrupted stream, no issues whatsoever, some of them transferred fine some not, so what could be the cause of these files being corrupt? is it some codec I'm missing?

More info:

• Files did worked on windows before transfer.
• When I transfer the corrupted files back to windows they are still corrupted.
• I use both VLC and my own app with VLCJ (in both the files don't play).
• File size is the same on corrupted and not corrupted.

File size also seems to don't matter, some files are just 12Mb long and some are 16.5Gb and both get corrupted.

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