When importing a Static Mesh into UE4 that is using the SOCKET_ naming, and is part of a Level of Detail set, the socket is discarded.
If the Level of Detail set is removed from the Static Mesh, then the socket imports correctly as expected.
1. open max and create a teapot, a box and a dummy object.
use the teapot as the object to export and just call it "Object", rename one box to "UCX_Object" and the dummy as "SOCKET_Object".
2. Select all those three and do "export selected" as fbx (In any case I make sure "Animation" is set in the fbx settings).
Import in UE4. (Make sure import LODs is activated). We got the object, the collision and the socket normally in the uasset as expected.
3. Delete the mesh from the content browser.
4. Create a box (name does not matter) and group it with the teapot.
5. Create a new LOD set from this group using the Level of Detail Utility.
6. Re-export and import into UE4
7. Notice how the Socket is now gone.
Outcome: Socket is removed from Static Mesh when exported with an LOD.
Expected: The socket and the LOD's import together correctly.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-23065 in the post.