Party boss return times
Returning to the world keeps field bosses on cooldown for the whole party.
Leaving a dungeon could recreate a field boss before its return timer had expired on a companion. Rebuilding the world now checks every current party member and keeps that boss defeated until the longest remaining timer expires.
The boss then returns normally. Each character retains their own saved timer; this fix does not copy cooldowns between characters or change boss rewards and return times.