Adobe Media Encoder renders oddly (Audio and Video)

I've rendered a few sequences through AME recently and they've all ended up strange. I believe I tracked one of the problems to the Metal render engine - Vimeo , but the latest issue has me baffled. Essentially, my sequence audio mix renders at the wrong levels. Playback and renders out of PP directly work no problem, but AME doesn't execute them correctly.

Here's the correct mix - Vimeo

Here's the incorrect (AME) mix - Vimeo

Anyone got any thoughts? I've tried cleaning the media cache, I've tried resetting AME preferences, so now I'm at a loss.

My machine:

2013 Mac Pro 3GHz 8-core

AMD D700's