This is a bug deal with those usable stackable item only.(I think...)
I have tried Wheat and Barley
When I put them in my item quick log(1 2 3 4 5)
and use them by pressing the coressponding key,
the whole item vanishes and does effect (+Health)
But after a while, in 5 seconds
The item reappear in the item quick log but with no deduction in quantity of the item.
Below is some screenshots illustrating the bug
Food gauge NOT full, wheat quantity 20
Pressed 3, effect taken, food gauge goes up, but the item vanishes.
After a while, the item reappears but with no deduction in quantity.
Hope GMs fix this soon if it is abnormal.