Why do assets imported in using Import to Level disappear even after Save All?

I’m working UE 5.5.4, Ok, so I imported a bunch of animated assets in from C4d 2025 using Import to Level and Saved All and Saved Level and saved All about 100 more times. When I quit, or crash and I reopen they are all missing. The Geometry Cache Actors are like placeholders but all the meshes are gone and I have to reimport them. I can’t put the Geocaches back in place they go red when I try to insert them in the place they were before.

Why?!!

This is the biggest waste of time!

It literally takes hours to import some of these files and boom gone in seconds.