It seems while Season 8 is simplifying endgame boss summoning it’s also slowing it down.
A New Dungeon Reset Angle
One of the better changes that arrived to Diablo 4 was Blizzard removing the requirement to reset the boss dungeon after completing a run. This sped up boss runs and removed unnecessary busywork. However, the boss are slowed down once again on the Season 8 PTR, due to the new chest mechanic.
After a boss is defeated, all players have a chest they can open if they have the key. However, as pointed out by NoRulez112, it seems there’s a 20-second timer during which you can’t re-summon the boss, and it starts after the last player has opened/interacted with the Horde chest.
This adds up pretty quickly when players are running the same boss over and over for some specific loot. Which is most boss runs.
It’s certainly important that players have enough time to open their chests. However, it’s also important players can’t grief each other. And, even if everything goes smoothly, that unnecessary waiting is removed as much as possible.
It’s the PTR
This is still the PTR, of course, and there’s still plenty of time to change the timer. Hopefully, Blizzard can find a good middle-ground solution that helps both players who are slower to open their chests, as well as those speedy farmers!