The Phaaryl Megalith

Encountered an interesting bug in The Phaaryl Megalith unique map. Finished the boss gauntlet by myself then had someone else join me for a trade, they accidentally went into the portal and came back, after the trade when i went in the portal there was a second Greater Rune (Alacrity to be specific) spawned inside (which i wasn't able to pick up and i assume its because its bound to their character) Wanted to confirm this so had a friend join me and when they went in they also got a Greater Rune spawn for them.

I'm not sure on the exact reason why this happens as when i tried to recreate it another time after that another rune didn't spawn. 2 things were different for that
- a bit more time had passed
- someone was inside the instance already

One thing i wasn't able to test, which might be a problem if exploited, is if the runes still drop after reaching the party cap (if this were the case you could technically get hundreds of greater runes from a single unique map)

I would appreciate if someone else could test this further by:
- Joining the Phaaryl unique map with as many people as possible and clearing.
- having everyone leave the instance and the party leader replacing the other members.
- having those new members join the instance one by one to see if new greater runes drop for them.
- make sure to always leave the instance empty as a new member joins and also keep track of the time to see if its based on an internal timer.