Opus files pitch-shift when unlocking iPod

[The Eight-Bit Link]

When unlocking an iPod with iOS 9.3 and VLC 2.7.2, the audio slowly pitch-shifts up and stutters while on the lock screen, then goes back down after the screen turns off or the iPod is unlocked. This does not happen with FLAC files. I can record a preview of what happens if you need.