Discussion/Question about Leavebuster system

Alright just to throw this out there right now, I am not trying to appeal anything or go against anything that is already implemented

Now that thats out of the way.

So i've played all of my provisional games, got ranked Silver IV after that. Few days go I playing regular and some ranked games then I was playing a bunch of bot games to try new champs that were free/I bought. Well that day I was having irl issues and have to afk 3 games that one day (all bot games), but prior to this I had not AFK'd a single game in months (to my memory), Now, my problem/question is why is my rank gone? I got a message about being in lower priority queses and what not, everything was okay, didn't really have a penalty or anything but now my rank is gone. Is this something that is supposed to happen or did I do something wrong?

** Just to make things clear, It wasn't really a de-rank, it was a reset. Like it acts as if i've never played ranked at all...