Hi R.!
I understand what you're saying. My daughter, now 18 months, acts like that with me but no oneelse. She has for the past couple of months. My husband and I do things the same but yet she acts out for me (kicking at diaper changes, running from me, smacking when mad, etc.) My husband would say the same as yours, "she doesn't do that with me". Argh....
I was getting frustrated and thought I was doing something wrong. I talked to my mom about it and she was very reassuring.
I'm not sure the psychology behind this but my mother (a nurse, mama to 4 girls, 3 step children, 9 grandchildren) assures me this is perfectly normal behavior to display with the primary care giver.
What has worked for me is to be firm and calm when my daughter does these things. If she hits (which is really rare now) I would gently hold her hand and give her a calm, firm "no", "hitting hurts" or "stop". Took a few times doing it but be persistent. At diaper changes I give a toy I know she likes and that sometimes works, other times I have to give a firm yet gentle "no".
What ever you do, be consistent and stay calm.
Don't know how helpful I was, maybe someone can elaborate on this for you.
Good luck to you and best wishes!
*I wanted to add this. My daughter acts like this mainly when she is tired. When I see she is getting worn out I go ahead and put her down for a nap or to bed. It has helped us a lot.