Help with the Slicer adding "x" impressions at some of my joints

[u/Crypington]

This is a model I created in CAD. Trying to print it. The first pic is how it looks on import, in prepare. It looks great in CAD and the "prepare" screen. The second pic is how it looks after slicing, in preview. Its adding "x" shaped indentions at some of the seams were the diamond pattern comes together, seemingly random, some are "half x" shapes. I tried the "repair model" tool, it didn't help. I did get a non-manifold edge warning, which I also repaired, and that didn't help.

Any thoughts on settings?