LO's Aunt is Cold

I was at my MIL's yesterday with LO almost 2. My SIL happen to be there with her kids (3 and 10 Months)

She just doesn't interact or acknowledge my daughter. My LO sometimes looks at her and goes over but she doesn't react at all. We were in the backyard and she said she's going in to get something to drink for the kids. She came back with 2 glasses only for her children. I then went in to get another glass. Another family member mentioned how my SIL is completely disinterested. I've seen her cradle and play with her friends kids.

I remain neutral by playing and interacting with her kids. Sometimes when I see her toddler I give her a small present to eat. It kind of upsets me that my child is treated like a stranger by her aunt. Is there something I should do or say? I prefer to avoid her but this time I didn't know she was there.