12 week old puppy suddenly poops anywhere but her pads

I have a 12 week old Chizer, who we got whenever she was 8 weeks old. She's had accidents here and there, but has mostly been consistent with going on her pads or in a safe spot outside. The issue is that this past week, she's been pooping anywhere BUT her pads. She's especially been pooping in her playpen, which she only occasionally pooped in there until recently. I clean the area meticulously with an enzyme cleaner, but she does it every time and I just don't get it. I give her ample opportunity to go on her pad or outside, only for her to poop in her playpen seconds after I put her in there. The playpen space isn't too big, either. I don't know what else to do. I've been attempting to retrain her on potty training, but it's harder this time around than it was the first time. Please help!!