I don't know. This happens to me, if I open the conversation then my phone lags and I back out of it, it says it's a new message & that I haven't read it.
Someone can tell if you're in the Kik app, though, because it's a darker shade of grey. If you're not im the Kik app, it's a lighter grey 'd', almost white. That's how you know if someone is ignoring you & read the message without opening it.