When a recipe finishes, the amount of items produced is listed in the sentence displayed in the result popup.
The number displayed on the item icon however represents the new amount of that item in your inventory.
Let's use the Flickering Fire recipe as an example.
Failing the recipe will result in the gain of 1x Black Ash.
The sentence in the popup will refer to that.
Should you already have some Black Ash in your inventory you will see the new total number of Black Ash displayed on the icon.