My dog is 1 1/2 years old and has been crate trained since he was 6 months old. We returned home the last two nights to find that he had lifted his leg to pee outside the crate. We had taken him out before we left on both occasions. He wasn't alone for more than 4 hours either night and he has been in his crate up to 6 hours without having this problem. How can we remedy this situation? Thanks