She probably never liked it but is getting older and more assertive. She has a little bit of "don't eff with me."
If you want to do something about it make her associate hugging with good things. Give her a hug mark it with a yes like you would obedience or with a clicker if you insist on the extra equipment and then slip her some treats. Rinse and repeat. She will learn to love hugs.
It's a good exercise to do with new puppies. Sorta rush at them with arms held out excitedly saying their name or puuuuuuuppy! Mark it then give food immediately. They learn to deal with people approaching them like an idiot.