I'm having the same issues here times two! I have 3 puppies ages 10 months, 8 months, and 4 months and the only one that is totally potty trained is the 10 month old. The 8 month old is 60/40 trained and Lula my 4 month old thinks she can pee wherever, whenever. I'm home with them all day, but if I take my eye of of her for ONE second she's already done her business and if I leave my fiancee to watch her, forget it! She pees all over the house.
Just today I spread out my xpen to span 1/2 of my dining room, only giving them access to the half totally lined with pee pads. I'd like to be able to teach them that pee pads AND outside is acceptable.. but I'd prefer only outside potties.
Anyhow, I feel your frustration