I cannot share any pictures ufortunately. I perform the association by first associating vertices to points and then edges to curves.

The geometry overall is complicated but, it's made of mostly straight lines so associating them is straightforward. Also, the 3D edges adher to the associations I made in 2D. The associations I think are not an issue. It's the loss of edge grading information.

I also tried to run the Checks/Fix but that doesn't solve the issue.

Ideally, should the grading be maintained when 2D to 3D rotation is done ?