I'm sorry, I wish I had the answer but.........my Abby does the same thing
If I need to leave the house, I put in her crate. I always take her out to potty before I leave. I maybe gone for only an hour and I come home and she has peed in her crate. The crate is big enough for her to stand up, turn around and lay down.
Tonight I just took her outside to potty before she goes to bed, she peed then came up on the porch to come in the house, came in and shortly after coming in, she pooped
I am almost at my wits end with this. I have NEVER had this much trouble potty training any of the other yorkies I've had.