I refactored the private merge() method to mergeLocal() and updated its JavaDoc to reflect what it actually does.
Likewise the public merge() method duplicates mergeLocal(), so I changed its implementation and JavaDoc accordingly. The nomenclature is still confusing, of course. It may be that the public merge() is only invoked from com.jme3.scene.plugins.blender.textures.UVCoordinatesGenerator, in which case perhaps it should be refactored out of the class.
I also couldn’t resist adding/correcting some missing/misleading JavaDoc not connected to the bug.