This is sounding more and more like a trainer related issue. If people who play retail suffer from this bug i think it's trainer related probally 1 or 2 options that are causing it. But i'm not sure. I'm going to try and play without the trainer for a few missions see what happens.
This wasn't a trainer issue for me, I played without a trainer for the first bit 'til I saw there was one, and I had the issue before I used it.