All UCX_geometry that have bounds larger than its geometry flicker when in Player Collision Viewmode.
Tested in: 4.21.2 (CL - 4753647), 4.22.3 (CL - 7053647), 4.23 P5(CL - 7838574), 4.24 (CL - 7861540)
Expected: The viewport shows all objects that take player collision
Result: The imported mesh flickers
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-78570 in the post.