Did you bought the red underwear.?I think Branda can´t steal panties, when Kelly has only the white underwear. This would lead to a logic stucking next day. So i think Brenda checks for red underwear bought.
Go apartment and click phone and use the fapp button. This allows you to buy the red underwear.
You also need first halloween party finished and wear the 450 top and skirt and go without bra (i dont know if no bra is needed to trigger Branda stealing panties).