:welcome: This is great website, you will like it. I"ve learned a lot here, but am still beginner, or i'd give you some advice, but i'm not super up on toliet training.
If you post this exact issue, in "behaviors" ...Someone will spot this and either give yo some help, or, point you to a thread where someone else had same trouble.
See, this here "welcome" thread, sometimes folks don't always read these.
So far, i can think you have to, have to, clean that spot up as best as you can to remove any smell as best as you can. Sophie can smell it and maybe gets some trigger from the smell to repeat the behaviour...from that advice on, the rest of this advice, keep in mind i'm a rookie, so stand by for better potty training advice.
Maybe, block Sophie's ability to get there. Seems weird that she is doing this at 2 years old...maybe she is adjusting to the denver house still, and just developed a bad habit before she understood where to go....?
Is your dog away from YOU while in Denver? Is someone else having to train this back out of Sophie, or you are in Denver with Sophie, too?
you might have to resume "potty walks" again, like you did when she was a puppy, and praise her for pooping outside. some folks may say she has to be crated if not supervised. But lots of good help is just around the corner!!
Is she home alone when this occurs?
Maybe you will get more att'n and better advice from others if you post this issue under "behaviours" Click on the "lounge" sign up there, and scroll down to the behaviours posts.
HANG IN THERE!! re post in behaviours, they'll see you over there.