Villager trading - able to continue trading even after a trade is blocked

Hi,

 

I am able to continue trading even after the trade is blocked. I am able to continue trading for up to 20 trades even though after 12 trades, the trade is marked as blocked.

Currently able to reproduce for book trades for Librarian villagers. I tried for a few other trades but could not reproduce.

 

Simulation steps followed:

1. Librarian villager with the books for emerald trade
2. Have plenty of books (Like at least 20)
3. Select the trade so that items are loaded in the slots
4. Click on the emerald (on the right-hand side) to make the trade individually (No shift-click)
5. Observe after 12 trades, the trade is marked as blocked, but able to continue trading by clicking on the emeralds.