Reported: Ammunition spawned with the GM item command arrives with a quantity of 1, as with the Giga Arrow in the screenshot.
Found: Ammunition is not a stacking item in this version: its quantity is its durability, and the item data sets 500 for the arrow in the report. The GM item command ignores that value and gives every item that does not stack a durability of 1.
Planned fix: Ammunition spawned with the GM item command will arrive with the full amount its item data sets, 500 for the Giga Arrow. Work on it is starting.
Also affected: Dungeon rewards that are not stacking items go through the same step, taking the reward count as their durability, and will get the same fix.