Stacking Arrows

confirmed, clicking a "potion of weakness" to hold it, then clicking on another gives you 2 "potion of weakness"

Not able to reproduce, just picking up the item from the creative inventory right?

select one of the arrows, and keep holding/moving it, click on another arrow, and it will stack with it, no matter what arrow it is

here is a video
https://youtu.be/6YGrvpBsKIw

Either the last arrow you pick up or the first (I can't remember) uses its metadata for the whole stack.

Was going to post this but then found this issue.
It happens because all the arrows have the same metadata AND id.
Same thing happens to potions and enchanted books, but since they aren't stackable, it doesn't change anything to the item.
It should delete the item, just like any other blocks.
Here's a video I recorded: https://youtu.be/iOde9T8C4ns
Still happening on 15w31c