Weird Glass Distortion with Perpendicular Glass Panels

[martini2]

I have a very weird scenario that i have not encountered before.

Why is the image behind 2 panes of perpendicular glass so shifted?
I tried upping the refraction trace from 5 to 10 on the glass material and the global settings, and it had 0 effect.
Refraction IOR is 1.51.
This is not a natural shift. It happens to some degree from any viewing angle.

Any ideas?

[peerman]

See my reply in the other thread.