My mum keeps saying to my 4 year old that she will send some presents to Father Christmas from her

I’ve spoke to her to avoid confusion to my child that it’s only me who does Father Christmas. Any other presents just come from grandparents etc nothing to do with him

What else can I do as she keeps saying it infront of my child? So annoying. My child is so clever and switched on that I don’t want it to confuse her