I don't know what happened between you and you mother (and I am not asking) but if as a result she decided it would be best to avoid contact with you I would see that as your mother and/or sisters setting up boundaries to protect your mother.

She must have been badly hurt and this is her way of protecting herself. She is clearly not avoiding *all* contact with you but it seems she is not yet ready to get closer.

Under the circumstances you write of, I don't see her doing anything 'wrong' as such. I imagine it is painful for you to be excluded at family gatherings etc... But these are the consequences and impact of what happened between the two of you. So, I would give her time.

I don't believe parents ought to automatically forgive any and everything their kids do (or say). Sometimes, ones words/actions really hurt.