/summon Villager with custom villager trades

When using the command

/summon Villager ~ ~-2 ~ {Profession:0,Career:1,Offers:{Recipes:[{maxUses:10,buy:potato,sell:carrot}]}}

OR

{maxUses:10,buy:392,sell:391}

to spawn a villager with a trade for 1 potato for a carrot does not work. I have tipple checked this command and i'm sure i'm not correct. This must be a bug.

UPDATE: All that happens is a villager will spawn but it will not have any trades. It is a villager with an empty trading inventory..