In 2x16 Rumple promises to teach Cora the art of spinning straw into gold in exchange for her firstborn child. But...her first-born is Zelena and she's already born (she's clearly born before Cora marries Henry) so did she trick him or just sell Zelena? Later she makes him change the contract to their child which they will never have?
Also, why don't Eva and Cora recognise one another? Eva destroyed Cora's life by telling Leopold about her theft and taking her fiancé. Also, why isn't Eva Queen yet as she married Leopold shortly after Cora is cast aside. Yet (I assume about a year later) Eva is still just a princess randomly visiting other suitors (like Henry) and doesn't remember Cora at all.