Item entities will only merge if the entire stack can fit.
Example:
Toss 63 stone on the ground at once, and do it again. They will both have 63 Items and not merge.
Toss a stack of 2. There is now 3 entities, but only 128 items.
This can cause issues with there being slightly less than double the necessary item entities. I have had farms that due to the nature, produced stacks of 33 items at a time, which would not stack.
Comments 3
"can't confirm" when you don't seem to understand the issue reported is rather misleading.
"a stack of X" means dropping a stack with a count of X items.
The expected behavior is that the single item stack of 2 items gets merged with the other 2 stacks of 63 items, making 2 stacks of 64.
I can't confirm this issue. I check a lot of times and the result is that 2 stacks of item throw on the ground will still 2 entities and still 128 items. Also idk what is "a stack of 2" is? A stack with an item name "2", or 2 stacks of item, or 2 item...?