Didn't get deserter debuff, why?

I'm leveling an alt and was doing a dungeon. After like 20m I saw a loading screen and had been removed from the group and the dungeon, but I didn't get any kind of deserter debuff. It didn't say I was kicked, just that I was removed from the group. I was able to immediately re-queue for another dungeon, no penalty. So was I kicked, and if so how come I didn't get a deserter debuff? If I wasn't kicked, what could have happened that made me leave yet not incur a penalty? Was a blessing in disguise, I hated that dungeon.
Dungeon deserter generally follows these rules.

1) if you have not killed a boss you will always get deserter (kicked or leave)

2) if you have killed a boss, but have not been in dungeon for 15 minutes then you do not get deserter but can not queue until 15 minutes are up (since dungeon started, not a fresh timer upon leaving)

3) if you have killed boss and are more than 15 minutes into dungeons then if you leave or are kicked you can instantly requeue.