my dog is doing the same thing. Just when I had patted myself on the back for training him so quickly and easily.. He came back from the vets to get neutered & it’s been a nightmare ever since. At first the vet told me that he could be overreacting to a cortizone shot and that it would go away. It did start out that he had to go every 15 min.. then a day later 20 min.. & then 30.. but now over a week later, he can hold it for a couple hours here and there, but then all of a sudden he will just pee every 15 minutes again. or like you said, come inside and pee immediately after having gone outside to pee. I didn’t know if he was just traumatized by the whole “snip snip” or what, but I need to figure out something.