Rule 613.7k

A sticker receives a new timestamp each time it’s put on an object. If the object a sticker is on receives a new timestamp, the sticker receives a new timestamp immediately after that one. If the object a sticker is on becomes part of a merged permanent on the battlefield, the sticker receives a new timestamp at that time. If an object has more than one sticker on it as it enters a zone or becomes part of a merged permanent, the relative timestamp order of those stickers remains unchanged.