Honestly a really nice detail. They coulda just lazed it and popped up a "you have too much in your inventory, move to item box?" But instead they added some extra unseen dialogue incase you had max invent
A lot of games actually have ways of handling items in inventories or inventories being too full. Borderlands typically give equippable items when you finish quests, but if your inventory is full... they'll bypass the limit and give you the item anyway, but you can't pick up anything else until you go back down the limit. The earlier Resident Evil games typically need you to wield the rocket launcher as part of the final boss fight, a weapon which also takes up two inventory slots. In order to ensure you can pick it up when the fight starts, the game requires you to carry either two items or a single item that takes up two slots in order to trigger the final boss fight, which clears up the space for it. In the Horizon games, Aloy has a few interesting responses depending on her quests if they require a specific item or a quota. If you have met the requirements for a fetch quest, Aloy will just state as much and hand over the item(s), continuing the quest. In Breath of the Wild, if a character needs to give you an item and you can't hold it due to inventory limits, they offer to hold it until you have a free item slot.
That'd be the Amon fight in this game. Had my xbox series x crash three times when Amon got to his last bit of health and spun kick too many exploding boxes.