My refrigerator extinguishes while driving, . . .

Tape it up...that's the trick. Easy fix. I have done it on all 4 of my rigs. Just because someone makes a cover with that much venting does not make it right. You might as well have no cover at all. It is perfectly fine to run LP at all times...forget about 12v. If the flame goes out it will shut itself off. I just use clear packing tape on the outside...simple fix. Glad to see you got the fix you needed.