I have many dogs who do this occasionally, but the major culprit is Marigold (a 2-year-old female tiny pin). I adore her and would do everything for her, but she will not stop pooping/peeing inside, even after I take her outside!! I take her outside every two hours for roughly 16-25 minutes, but she refuses to go. However, as soon as I take her inside, she squats and lets loose, typically in the restroom. She only uses the restroom outside in the morning. I untie her from my bed (she’s leashed to my headboard when we sleep so she doesn’t fall off because she’s prone to falling and my bed is very high) and carry her outside (because if I let her walk, she’ll poop on her way to the door) and she’ll go as soon as I set her down, but that’s it. You could believe I am not giving her enough time, but this is not the case at all. Sometimes I lose count of time and spend more than an hour outside, and she still waits for us to come inside. I don’t blame her, though, because she has certain neurological abnormalities caused by brain trauma she received from people she was bred. I just wish she’d stop holding it till we went inside, so if any of you guys have advice on how to address this, that’d be awesome!
You gotta give her credit for doing it in the bathroom. She’s probably saying “Well this is where Mom poops, so I guess it’s where I’m supposed to poop. Wait, why is she so mad?” 
My ferret did that. If he couldn’t make it to a litter tray, he’d run into the bathroom and go behind the toilet.
I couldn’t get mad, because ferrets literally can’t hold it so it wasn’t his fault really, and…well I guess he wanted to be like me?
LMAO I love ferrets. It’s like they’re made of crack. The ferret we had would just load up one corner of his cage with poop. There was a mountain every day.
My Dog pees in my wheel inn shower all the time and I just think it’s so clever.
I don’t currently have a dog. But most of my previous dogs had to be walked off the property to get them to poop. They would not go in our yard.
Don’t come back inside until they poop outside. Bring a chair!!
I discovered that crate training was effective for this type of problem - confine her till she leaves. Place her back in her box till she poops. Then she can spend a few hours outside of the crate before the procedure begins again. Or a litter box in the restroom!
Have you ever tried taking her for a walk? Some dogs need to walk around to get things flowing. Even walking around the block could help.