15m old has horrible naps/nights when she sees JUSTNOMIL ?

I thought it was coincidence, but my gut tells me it’s not. Whenever my daughter sees my MIL, she has a crap nap and an even worse night. I thought it was because maybe we just happened to see her on busy days like holidays, or we just happened to see her whenever she was teething (idk how) but these are not the case. Every. Single. Time. Every single day she’s had a visit with/by her, she sleeps awfully. Is she picking up on my nerves when she’s around? It’s not because she doesn’t see her often, because we occasionally visit my relatives, who she sees less often than MIL, and sleeps absolutely fine. I did notice today when she saw her walk through the door, she clung to me tighter and just waved. When she sees my mom, I’m chopped liver. I don’t suspect anything terrible, but just wondering if anyone else’s babies/toddlers have shown a pattern.