Can someone explain to me exactly how dungeon CDs work?

[cletus]

Here was my understanding:

1. You can leave after the first boss with no penalty
2. If you re-queue and new people are added, you'll get the deserter (30 minute) penalty
3. This MIGHT be overriden by killing another boss. I haven't tested this. It's just speculation

But there's more to it. I've just queued 4 TW dungeons with a full 5-man, trying to get a Black Rook Hold instance. Instead I've gotten Vault of the Wardens 3 times (out of 4) and Darkheart Thicket once. These are all useless to me for the last 2 VotW I've killed the first boss and then left without re-queueing. Here's what I've noticed:

1. After the first VotW leave (the 2nd VotW overall), TWO of my FIVE toons got a "You recently queued for a Random Dungeon" message giving me 10 minutes before I can queue again. I suspect this is from a 15 minute overall dungeon CD maybe?
2. AFter the second VotW leave (the 3rd VotW overall), THREE of my FIVE toons got this 10 minute CD.

In both cases, the 4 non-leaders all left (so I wouldn't get the "do you want to reqeue?" dialog) and then the leader left. The group is 4 11 Warriors (1 Tank, 3 DPS) and 1 13 Druid (Healer). Every toon is XP-locked.

The leader was the same in all 4 dungeons.

So I'm confused, specifically:

- Why are some toons getting a dungeon CD and some not?
- What is the criteria?
- Is there any way to avoid this?

 

[Rahn]

This was changed sometime during the anniversary event, the dungeon has to be "completed" to avoid the penalty for leaving.

Supposedly a lot of people were completing one boss and then abandoning the group for whatever reason and Blizzard changed how the LFG penalties worked.