It sounds like a behavioral issue. He sounds like he goes back to his old settings when you are not around.
I would suggest restricting his movement when you are gone and go with a smaller kennel that is more like a den, covered and small enought that he would have to sit in his own mess if he goes. They typically sleep all day and the small space will make him feel safe while you are away. It may be a little stressful at first, but they really sleep all day. I wouldnt put any bedding in it until you see that he can hold it first, then add it as a special something for him. Add a few chew bones to help him use up his stress energy.
Get him excited when you get home and go directly out for a pee. Feed him next, and walk until he poops. Get him used to the idea of a routine that gives him praises when he does it right. LOTS of potty praising!! Maybe even treats!!
I would suggest the travel kennels because they are cheap. You shouldnt have to use it for long. Once the behavior stops, you might want to move him to a larger wire kennel (cover with a blanket) that he can stand in, but not much larger. Once he is cool in that and keeps the routine, then expand the space more.
It is important to give him guidelines that he understands and praises for goals he can attain. Mine grasp this idea very well.
A very regular potty routine will be essential. Anytime he is out of the kennel, immediately outside to "go potty".
When you are home, pick a time every day that you take him to pee. Not when he tells you he needs to go. Beat him to the punch and tell him to "go Potty", then once he goes, take a walk for the treat.
you will need to give attention to the potty time when you are at home to establish it is important so he will know it is also important when you are not home.
Ignore the accidents, dont scold, just clean it up and stick to your routine. He will slowly adapt to the new guidelines and follow your cues.