Advise Me

I just don't get this girl. Mayah will be 2 and a half tomorrow. She is growing in so many ways. She is talking and saying things that amaze me. She is figuring out her colors and even some of her letters. She loves to color and draw. She is quite an amazing little girl. She has been potty trained for me for about a month. By this I mean that she poops and pees on the potty when Will and I are home nearly every time. She has had very few accidents for us. However, she is not potty trained when someone else watches her. We were away this past weekend, and I got a text from my sister-in-law that Mayah had "fallen off the potty train." My mom and my mother-in-law both reported accidents when we got home, too. She even had an accident last time she was in the nursery at church.

I do remind her to go potty and sometimes sit her on the toilet even if she says she doesn't need to go. I just don't understand why she refuses to consistently use the potty for any one but Will and I. Has anyone out there had this experience? Does anyone have any advice? I'd really like to be able to leave Mayah with people without the fear that she will poop all over them. Help.