My puppy uses the bathroom outside but still goes inside

I adopted a doodle type dog over a month ago and generally it’s been going great. Shes about 8 months & is technically potty trained. At first she wouldn’t go potty inside at all but then about a week in she started peeing inside. From then, I stopped leaving her unattended & really focused on spending time outside & rewarding her when she goes to the bathroom. It was working for about two weeks. Now, I leave for work and she poops inside. I had seen her poop, treated her & taken her out before I left for work. My husband takes her out and he could do something simple like shower or run & get the mail right after and she has an accident. Am I not spending enough time outside even though she goes? Is it a separation issue even when there’s a person home? I just don’t know why it seems to go away & then come back?