Sudden loss of audio towards the end of a timeline

Very odd one here... I am editing from a Multicam source, using a single source of audio from it (e.g. unswitched). Everything is uber-basic, I just have a multicam composite source for now, still waiting for the ISOs to arrive. 

Everything is working smoothly, but I've just hit a wall where after a certain time in the program/sequence (my edit), I lose audio. Nothing comes out of the monitoring after a certain cut point, the VU meters drop dead. I have waveforms, I can match back to the multicam source and hear the audio; if I then overwrite/replace the matched section, the audio gets lost again in the edit... If I match back to the source audio material and replace the multicam audio in the edit, all is well...

I can exporty my edit and the audio gets out. Duplicating the sequence or copy/pasting all the elements into a new sequence do not help, the same problem gets carried over.

I have no audio track keyframes (no panning, no clip, no track volume, etc.), no camera cuts either, everything stays on that single souce. If I ripple/trim/extend the last segment where I have sound, the audio follows the extended part. But as soon as I add a cut, any segment following that cut is muted. But if I copy and insert-paste those muted segments earlier in the sequence, all is well...

I seem to have noticed this after doing a few extracts from my edit/sequence and inserting those back earlier in the program... or maybe that's unrelated, can't tell for sure. I have updated to the latest version of Premiere this morning, I have also updated my NVidia driver FWIW.

Hints anyone? TIA --Alain