We've noticed an issue with normals in the encoder. The normals on a particular mesh are randomly incorrect during import to the encoder (from a Maya FBX export).
I've copied, exported and reloaded the mesh and still have this random issue. The workaround we've come up with is to copy then delete the GEO in Maya and then paste and re-bind the mesh to the joints, 50% of the time this solves the problem on the first attempt, but it's also taken 3 or 4 copies to reolve the isssue.
When exported with the normals correct the WT3 file seems to work fine in the app.
I've attached an image below
I should say it works IF you copy/paste the mesh and then export straight away (we're using Maya's game-exporter to get the animation takes), any further editing of meshes before export appears to cause the issue.