Random Block appearing during print but not in 3d visuals

So this is a really odd problem I've had the last print I did and I'm trying to see if anyone else has had the same issue (searching didn't kick anything back). I recently tried to print a bit for 40k (bolter) and lychee keeps inserting a random solid block into the model when I slice it. It isn't there in any program I've opened the stl in. I opened it in UVTools and sure enough the block is there... It does not show up in any other slicer that I have tried (orca, prusaslicer, chitu). I've repaired the model in lychee and it was there. Then I took it into blender to fix it by hand, and that little block is still there no matter what I do! Kind of bummed because I've been loving the supports lychee generates vs chitu.

https://preview.redd.it/cavn9ga1r1ge1.png?width=1452&format=png&auto=webp&s=4fc017b08b0041b5c3ce8e5e15eadacad663cef1

https://preview.redd.it/2l3nica1r1ge1.png?width=1021&format=png&auto=webp&s=a2d66d45c18105e04d84c6d9f1069c1c9fb81d9d