Recording becoming buzzy/staticy halfway through?

Hello there.

I was wondering if someone could help me.

I am recording an audiobook and i was editing after recording a 30 min chapter. at around the 6 min mark the audio completely changes and sounds electronic and corupted, like theres a second buzzy voice under the main one as well as a bunch of clicks and this persists for the rest of the recording. 

I have no idea why this is happening, the recording is fine before the 6 min mark and nothing was changed in the hardware or software settings.

I also definately did not move any plugs and the issue is still there when I export it into a wav file.

Many thanks.