Tails didn't know her that well before she disappeared originally. He does remember hearing about Bertie having broken her heart but other than that, they might as well be strangers.

He was out and about since his shop hasn't opened for the day yet when he spots her. She isn't the one with the butterfly clip so no awkwardness there and she doesn't seem to be the Flutters so it must be the native Fluttershy that just came back.

He waves over to her.

"Good morning."