If you fish an item out of water and hold down right click after the initial click to reel something in, and you are looking slightly down at the ground, your fishing rod bobber will hit the item you just fished and take an additional 3 durability for trying to reel in an entity, even though you just fished it out of the water and the item is on your way to your inventory.
Environment
Windows 10
Java 8 Update 211 (64-bit)
Correct, the fishing rod can reel in item entities, this is intended.