We have 2 Lab puppies (5 months old) and they are both crate trained, and 1 is housebroken, but the other one will pee indoors, we have trained them both the same. They will be out for a pee, come inside and if the 1 has to go out she will go to the door, the other 1 will pee on the floor if she has to go. Not sure where to go from here?
I worked for a dog trainer for a few years who told me she didn't consider a dog fully housebroken until at least a year. Five months is still pretty young; your pups still have quite a bit of growing to do. It could be that the pup's bladder hasn't grown as much as the other parts of her body yet, so she may need out more often than you realize. A five month old pup needs out at least every 3-4 hours, every time directly after they eat, and almost any time they get excited.

Another thing you may consider trying is crating her as soon as she comes in from doing her business, and then letting her outside again ten or fifteen minutes later. She may be getting excited about coming inside, which makes her have to pee again. Never rub her nose in it--dogs just don't understand when people do that. It makes them think that the act of going to the bathroom is bad and you definitely don't want her to hold it until you aren't around.

Finally, I'd say if you aren't following her out to make sure she goes when you let her out, do that, just to be sure she isn't pulling a fast one on you.

I hope this was helpful, good luck!