It might be the hose.
I once had replaced a short LP hose on my popup with one from a hardware store. It worked fine for several months. Then one day the tank stopped working. I assumed it was empty, although it felt full to me. So I switched over to my backup tank. I took the "empty" one to a refill station that close to the entrance of the campground we were in. Turned out they were a big distributor for the area. So when the guy filling tanks looked at mine and said it was full, he picked it up and took it back to the techs in their shop, with me in tow. They hooked up my tank to a test burner and it was fine. Then they asked me a lot of questions. Sent me back to my camper to bring back the hose. They ran a scope into the hose and showed me how the interior walls were breaking down and falling apart. The hose was clogged with bits of hose and goo. But it didn't leak. They built me two new hoses (yes, "built", I watched them do it) for less than I bought the bad one for and sent me on my way. I never knew an LP hose could degrade like that one did. Since then, I had one other hose get clogged with "goo" and junk. According the guy from the propane shop, the oil in "dirty" propane can cause hoses, fittings and burners to clog up.