order of materials changes on reimport

Update: this problem is still present in UE 4.15.0-3258144, brand new project, with only one Static mesh imported. At the moment only viable solution is to work on the assests in version 4.13 and when model gets finished/approved then export it to 4.14/4.15p

----- rest of the report is for 4.14 -----

In my 3ds max asset creation workflow I use 1 dummy box as a master parent with all the geometry meshes and UCX pieces linked to it. This helps to maintain pivot of the asset even after serious changes of the asset's dimension and so on. Since upgrading to 4.14 i am frequently running into serious issue.

Depending on what meshes linked to the master parent and what IDs those meshes have material ID swaps after reimport.

Let's say i have asset made from multiple meshes and i import it into UE. I assing materials to the IDs and all is fine. However, if merge some geometry in 3ds max and then reimport, materials get randomly swapped.

To illustrate my point i made few screenshots:
This si my 3ds max scene. Both assets have same name and are essentially same. Except the left one has all the geometry merged together while one on the right is composed of multiple meshes. They both have same material with submaterials named 1,2,3,4.

If i export left (merged together) one, asset in UE looks as it should, all materials are in correct places.

If i export right one where multiple meshes are linked to export node, asset in UE looks differently. Notice how materials slots in the editor stay same but slots in the asset LOD0 section changes for no apparent reasons. (bottom right corner of the image.)

Another example could be changing small detail on asset and reimporting it again. It leads in to another random change.

Steps to reproduce.
1. Create static mesh asset composed of multiple geometry meshes linked to dummy box as a pivot node.
2. Export asset to the UEditor.
3. Attach all the meshes together, link the new mesh to the pivot node and export again.
4. Notice how submaterials are assigned differently to the asset.
5. This also happens randomly when 2 or more meshes are merged/attached together so the number of the objects in the hierarchy and ids changes, but it is harder to reproduce it.

Info that may be relevant.
I am using Win10, nvidia gtx 970, UE 4.14.3
The problem can be replicated in fresh project

I've posted this question on the forum hoping it was simple problem but no one could provide answer so i am looking for solution here. Link to thread

I cannot find mention about this problem on the internet so it's possible I am doing something wrong. Help please. Thank you, H.