if im not wrong, in NLA it should be only under Armature, not Vertex Group(but well i might be wrong)
this dont help me much to know the reason tho. But maybe someone else will know.
But, just to tell you, .Blend(because each version have different api) and .ogre(because deprecated kind of) exporters are very unstable. Current stable exporters are .obj / .gltf as example.
Maybe its because SDK 3.2.4 is compatible with Blender 2.8+ only? idk.
What i can tell you is rather some information. Myself i had issues with .blend exporter before, because it often break on different blender versions(because blender each version can change it).
So i can just suggest use .obj(static models) and .gltf(animated models) and using Blender 2.8+.
This seems stable and GLTF is new game export standard
- Blender 2.8+ -> export -> gltf
- SDK -> second click on GLTF -> convert to j3o (or just use gltf format, also possible)
i think you could try see link i provided earlier. For me it works very well. Both animations / shape keys and material export. But you also would need to know it export PBR material. so if you want older shader, you would need replace it manually via sdk or code.