Different behaviors when adding "dedup()"

I think the traversal is really weird. 

• first traversal: g.addV().addV().limit(0) -> creates 1 vertex
• second traversal: g.addV().addV().dedup().limit(0) -> creates 2 vertices

And limit(0) is also strange and I don't really know what the expected behavior should be here with Gremlin.Maybe there is a bug?