Steps to reproduce

Scenario 1
Fill farmer's inventory with the carrots ( 8 stacks max)
Let farmer plant 1 carrot in a farmland block
Farmer now have 7 stacks and 63 carrots in its inventory
Throw a stack of carrots, make sure farmer pick up

Scenario 2
Give a villager 7 stacks and 32 carrots, make sure it picks up
Now, give it a stack of carrots

Expected results
It can only takes number of item out of the stack to its inventory limit

What happens
It takes the whole stack - filling its inventory to the max and consumes the rest.
While farmer planting that freed up some of its 8th slot, able to harvests and picks up more than its inventory limit.

Note

Other possible scenario: villager with a full inventory of food sharing other villager, freeing up some of its 8th slot may be able to pick up the whole stack. This is wasting our time of growing, harvesting, and giving our food supply