Board Thread:Character Discussion/@comment-25355646-20150302022703/@comment-5106672-20151001162117

I've read an interesting fan theory about Rumple actually creating the Dark Curse, placing it in the care of the Chernabog and then retriving it when he new it was nearly time to hand it over to Regina. Which would also explain how familiar he was with the traps in the lair.

Doesn't sound far-fetched and might explain the apparent inconsistency. One thing is sure, though: the show could bother with providing these explanations to make the plot look smoother.