Must be a server specific issue. I've never seen that on Coeurl. If it's pulled at the announced and agreed upon pull time, nobody calls it an early pull. We'll get the occasional "Oh darn, missed it

" type of comments after a hunt, but without any anger to them.
But yes, it will sometimes take over 10 minutes. The first announcement goes to shout and maybe one or two linkshells, but it's not until the people responding to that get there that it goes out to their
other linkshells, and when that second wave arrives, they'll pass it to yet more, and so on. It can take a while, but that's the price of actually being polite and avoiding that drama some servers seem prone to.
Between tomestones and Allied/Centurio seals, an S rank gives around three times as much rewards as a dungeon that you'd spend 20 or 30 minutes on after waiting yet more time in queue. So if it takes more than 10 minutes for everyone to arrive, then you wait for more than 10 minutes. It would still be a great reward for time ratio at over twice that (though I've never known it to actually
take twice that long).