I'd be curious if anyone else can replicate this. I have a project with a slow Zoom A/B crossfade near the end of the video (the only non-standard transition). When it rendered, it was off-center during the zooming in phase then jumped to a centered more zoomed out view at the end of the transition. Very odd looking.
I replaced the crossfade with a Gradient Wipe. When I rendered that, it was exactly the same as above - never implemented the Gradient Wipe at all. Weird.
I'll report this as a potential bug. Simple crossfades and page wipes work fine.
Mike