The nausea effect is broken due to the new camera system.
Expected Results:
The image just gets distorted.
Observed Results:
Your head will move without your input;
Everything looks vertically stretched in certain points of view.
When facing north/south:
The screen rotates just slightly.
When facing east/west:
Everything rotates in a weird way, with your POV often going higher than it should;
Your crosshair is no longer an accurate indicator of what you're looking at.
When facing straight up/down
You'll keep switching directions;
You'll no longer be facing straight up/down when switching to Third Person View and back to First Person.
Confirmed, the animation seems to be much more exaggerated when facing East or West.
This bug can be seen when using a nether portal also.