The new Recipe Book that appears while viewing the inventory and/or using /recipe command displays what has been achieved/earned.  It also shows the recipes which is great and expected behavior.  However, after the user clicks on the Recipe book to open the Recipe Panel to the left things go badly.

If anyone clicks on any block for the recipe (left side), you get that block added or removed to/from your inventory. Click on the same block repeatedly and watch it being added and then removed depending on how many times it was clicked. Select a different block from the recipe and the previous one re-appears in your inventory once it counts down and removes it. Strange behavior and reported also on Essentials and CraftBook and the owner of CraftBook feels this is a Spigot issue to fix, not at the plugin level.