If you’re near a tractor supply or something similar, they sell propane by the gallon for a tad over $2/gal. Little less expensive than swapping tanks. filled 2 up and topped one off for $27 or so a few weeks ago, I think Publix wants $19 for an exchange.
Edit; didn’t really answer your question. it’s a regulator issue. not sure if the bigger tanks send at a higher psi than the smaller ones or what. the 22’s regulator would malfunction I’m assuming thinking gas was leaking and only flow to the point that there was barely flame at all. Never had a problem when I used the small green camping tanks, but about every other big tank I put on it would trip it and I’d spend half an hour trying to trick the regulator. there’s ways to reset it, sometimes they worked, sometimes they didn’t. Never had an issue on the 36 though. I would move it off the porch when it comes time to season. they put off a LOT of heat.