Time change, people change. Yep, that's a cliche thing you say whenever someone around you changed. However, when someone say the same thing to you as the reason of their different personality, will you believe them right away?
I mean, like some people will say that they have changed, maybe, for the better, how do you know that they really say the truth? You can't really tell how much this person changed when you're not even around this person for a year, right?
Time change, people change—however, some people need more time to change. You can't really tell. Maybe now, tomorrow, or by the time that you're no longer in the life of this particular person. Well, that is absolutely fine—
Just make sure it's not your lost.