Help with Potty Training

I have a 5 month old Shorkie. She has been crate trained for 6 weeks now – no accidents. She is also 100% trained to go potty every time I take her to her area in the backyard. The problem is she pees in the house every time she is out of her crate for even a minute, even if she has just gone pee outside. I’ve had her since July and she has basically been in her crate or outside. I thought I would let her out of the crate for a few minutes and build up the time but she has never gotten beyond the 5-10 min mark before peeing inside. I only let her roam the house if she has peed outside. Any thoughts?