VR Converter - 2D source to Fisheye(Fulldome) issues

Hoping someone here may see and be able to help. I'm creating a dome animation with a 2D graphic background. It seemed straightforward. 2D source Input to Fisheye(Fulldome) but I'm getting a ton of pinching on the top and bottom. My input comp which has a very grid-like background is 4096x4096 with lots of animation, again, mostly 2D with some video and images, nothing crazy. See the image for the pinching at the polar coordinates. Also strangely, when my comp that has VR converter applied on it which is 4096x4096, VR converter shows nothing, when I set it to 4095x4095 it seems to work. Any tips would be appreciated.

Also, the footage is not built as a 360, the grid is not perfectly seamless and it causes issues when created in a 6 sided box environment and animation would be much more difficult to have to map into a full 360 space.