Wandering Traders Don't take buy item but still give sell item

So I was playing near a village and found a wandering trader carrying blue ice for only 6 emeralds. I put the emeralds in the correct slot, then shift-clicked on the sell item. It put the ice in my inventory but didn't take any of my emeralds. It must have something to do with the fact the trade was used up after this purchase. I tried it with the other items he was selling and it worked for all of them. I would only give me one of the item though, even if it probably should have given more. And it only happens when you shift click

 

Link to demo https://youtu.be/tl2ZR5YxCMo