(sry 4 bad English)
Hi, I have the same problem. Now, the problem is: BlockWall definies 2 variants: Mossy and normal cobblestone. Vanilla is just ignoring them automatically, but you have to ignore them, too.(Like the POWERED attribute at doors).
ModelLoader.setCustomStateMapper(block, (new StateMap.Builder()).addPropertiesToIgnore(new IProperty[] {property}).build());
This is the way I ignore properties in blockstate files.(put it in preInit)
But this doesn't worked for me, just for doors.