Inexplicable audio problem in Cubase 6.5

This problem has only been happening on two particular projects of mine. Playback will be all normal, until at random one of the audio tracks will cut out, the volume meter shoots up to the maximum level, though there’s no actual audio output, and then it just sits there for about 30 seconds before going back down. After that, i’ll play back that section of the audio track, and it’ll play back a completely different audio file from somewhere else in the song (usually from a different track too), followed by a sort of click, then back to the file it’s supposed to be playing.

The files it jumbles up remain the same no matter what I do, I can move the audio file around, put it on a different track, etc.
Anybody have any experience with this issue? I’ve tried searching everything I can think of, and nothing. It’s like cubase is confusing which files are where or something. Sometimes I can put the transport bar on the offending section and the disc cache meter will flip out and hang at 100% indefinitely. I’ve already tried moving the project to a different drive, same thing. So it shouldn’t be a drive error. I’ve also confirmed it’s not a VST plugin/instrument issue as I removed every single one from the project to no avail. The audio tracks in question never had any plugins on them to begin with.

Any help would be much appreciated because I’m losing patience with this.