TinkerGraphCountStrategy can return wrong counts

gremlin> g = TinkerFactory.createModern().traversal()
==>graphtraversalsource[tinkergraph[vertices:6 edges:6], standard]
gremlin> g.V().map(out())
==>v[3]
==>v[5]
==>v[3]
gremlin> g.V().map(out()).count()
==>6
gremlin> g.V().select("a")
gremlin> g.V().select("a").count()
==>6