the Mai from the beginning of the manga, after hearing the "I luv u too" from Tae, would have taken Tae into her arms and kissed the living daylights out of her!
I really don't see that happening. Even when she was less concerned about the results of her actions, that would have been a step too far. A hug, yes. Maybe a kiss on the cheek. Possibly a very chaste one on the lips if she was in the right mindset, but the situation really wasn't suitable for that. But "kissing the living daylights out of her"? No way.
I have also seen absolutely nothing in this series that would in any way constitute a retcon; nothing of what has happened has been in any way changed by the later chapters.