Sim won't stop "sneak walking"

I guess that's what it's called. The walk a Sim does when they're trying to sneak away. My teen Sim has pulled alot of pranks lately. She had the "got in trouble" moodlet and just was released from being grounded. Her relationship with her parents is BEST FRIENDS with dad (all the way green) and DISLIKED with mom (all the way red). Sadly daddy died in a fire, leaving her mommy in charge of her!. She now "sneak walks" in the house (to go do her homework, go to shower, go to eat dinner, ect.), even if her mother is right there in the room watching! If she was in trouble, ok fine sneak away from mom and go have fun! But right now, she's "off the hook" and not in trouble! So why is she STILL "sneak walking"? It started out funny as she did it the first few times. She did it to go to her prom since she was grounded. But it's becoming annoying- very quickly! How do I get her to walk like a normal Sim?