What I expected to happen was...:

If there is only one item dropped on the ground then it shows only one item.

What actually happened was...:

There is a situation where it shows two (or more) items, but there is still only one.

Steps to Reproduce:
1. Execute command /clear

2. Execute command /give @s minecraft:ender_pearl 577

One pearl is dropped, it looks fine

5. Walk into dropped item, it doesn't get collected because you have full inventory, that's ok

4. Drop entire stack of pearls using CRTL+<Drop Item (defaults to Q key)>

5. The one pearl gets picked up, ok

5. Pick up stack of pearls you've just dropped. You pick only 15 since your inventory is now full.

6.  See that there is only one pearl remaining on the ground, so it should render as single, but the game renders it as two items.