I have never had a changeover valve leak propane with 1 bottle removed. in fact my 5th wheel uses 4 grill size bottles with 2 auto changeover valves. I can remove one tank to get it filled, and return 1 week later and no leaks.
on my Wolf Creek it has one that looked like the Cavagna shown on amazon. I had it change over once but stay green. I had the refrigerator stocked for a trip. the morning before leaving I opened the refrigerator and it was 75 inside, both tanks were empty and valve was still green.
I have the same valves on my Arctic Fox but its always turned red on failover.
but after the Wolf Creek failure, I bought a Dometic LPGC10 LP Gas Checker and always know the level of the tanks