Normally propane white outgassing is liquid propane and is VERY DANGEROUS. You said it is coming out of the top?? does your regulator have a knob on the top to choose tanks?? or a window to tell you if it has switched for you? It could be someting as simple as an overfilled tank that has not been vented at the 80% fill. Or a bad regulator. There should not be any liquid in your propane system, let alone a white liquid. My reccomendation is to let a pro check it out. it may cost you a few $$ but you will know that it is safe.
WBCCI #5501 AIR # 49
1978 Argosy 28 foot Motorhome
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