Project background does not copy 'Camera Shift' parameter

[scottagecheeseandcrackers]

I seem to be having a recurring issue - where the project background gives me a texture which is not correctly aligned with the background image. I get around this by manually copying the camera shift parameters to texture projector camera.

If it makes any difference - in movie clip editor - I always select Optical Centre - 'from 3rd vanishing point'

Attached is some screenshots showing the issue.