iMessage stopped doing delay?

So, ever since iOS 6 and ML, if I started a conversation with somebody on my computer, I would be alerted to a new message from them on my computer. If I didn't open iMessage to view it within about 10 seconds, then I'd be alerted on my phone.

Same with my iPad... etc. Wherever I started talking with somebody, the conversation would stay on that device without alerting other devices until I left and continued the conversation from a different device.

Now, no matter what device I'm using, I'm being alerted everywhere at the same time. I'll be trying to iMessage with somebody from my computer or iPad, and my phone buzzes like crazy with each new message.

This has been going on for about a month, and I thought maybe iOS 6.1.2 would solve it... no luck. And again no luck with 6.1.3.

I've tried turning off iMessage and then back on on each device...Nothing.
Is anybody else experiencing this problem, or even know what I'm talking about? Does anybody have any suggested solutions?

 

I don't know.
All I know is that the way it was doing it before was MUCH better... Whether it was the intended behavior or not.