My DD2 who is 2y8m has been toilet trained since Easter, over the last couple of months she has started to wet her pants, most times, if I ask her to sit on the potty she will but if I don't keep up with asking she will go in her pants take them off and put them outside the laundry. I have tried to find out why but I really have no idea. Throughout all of this she has still be happily taking herself to the potty to poo but over the last couple of days she has started to poo in her pants as well.

Any suggestions?

I was going to start a reward chart as I think that this is something that she will really respond to, being able to put the sticker on but it still worries me why she is doing it to begin with.