Noise Error / split frame

[OuterGamut]

I am getting an odd rendering error where the rendered image is split into a good looking image and a very noisey one vertically. image attached.

The image looks fine in the IPR but renders started from ROPs ( Render to disk) are all coming out this way with the split in the same position.

Houdini 19.561 / octane Octane_2021.1.4.0

I didn't really change much except some texture settings and light positions when this started happening - now I cant get it to go away. I can PM a file

[OuterGamut]

I have narrowed the problem down to the camera in the scene- its an imported fbx camera from syntheyes. A new camera does not render the split error.

** false alarm - somehow the right crop slider was moved either by errant key or mouse hit. **