Hello:
So, there could be a few reasons for this.
One reason could be that the scaling is negative. Make sure that there are no negative values in its TRANSFORM.
Another reason could be because the materials do not support Nanite. So, try disabling it.
The other I can think of is that SUBSTRATE MATERIALS needs to be enabled… I’m assuming that these are NOT native materials to Unreal, and that you created/downloaded them:
What I find interesting is someone else had a similar issue, but it was STATIC meshes, not movable, that were the issue:
Try diagnosing the issue by using NATIVE materials on those meshes to see if the problem persists. If it does, then there’s an issue with your project, and I would suggest migrating the entire thing into a fresh/empty project.