Artifacts when MPV plays same file located on another disk

I'm facing a peculiar issue. I've copied media file to USB flash (using Linux Mint). Now when this files is played by mpv at one point it freezes for some time displaying what looks like green foreign language symbols all over the screen (and no subtitles after unfreeze). When played from initial disk it plays fine. Hashes as calculated in terminal are same. I wonder how playing same file can lead to different results.