"update data" does not find conflicts

[skyper]

I canceled an upload. (It was near the end as later all changes where uploaded already).

There existed only on data layer and validator at that moment.
I updated data and no conflict was reported.
I added one more node and dried to upload but then I got several conflicts, all because of duplicated ways/nodes and there relations.
I ended up with just my singled node left to upload after resolving all errors and conflicts.

All these conflicts should have been reported by "update data"
(By the way, conflicts which are already solved are still shown)

r3652