Villager Trades bug.

Hello Support!

I want to report a bug that is really annoying when im trading with my villagers.

First, i trade a lot of sticks with a fletcher to obtain emeralds. After trading a lot, the villager changes the price from 32 sticks to 50 and the price will change to 64 and more sticks. 

I tried to revert the price to normal transforming the villager to a zombie and then, reviving him with weakness and a gapple, but this doesn´t work. Also, i tried with the Hero of the Village effect, but i obtained the same result, nothing. And no, i didnt hit any villager while i was trading.

Thanks for reading! Greetings from Argentina. (The bug is affecting from the 1.14)