The valve is not the same as the adjuster, which is easy to check first.
Your leveling system works, it’s just the travel mode/ride height side that’s haywire, and when we had similar symptoms it was that little rubber coupler that was the culprit. In our case it was the single front one, but your left rear one is ether cracked/torn or has slipped and is not holding it’s prescribed position.
All that said, I must allow for the notion that your coach’s ride height system may differ from others we’ve worked to analyze before.
Joel