Our propane regulator failed and was leaking from the body. Not a connection or hose. One telltale was that the indicator was showing red even though propane was flowing. I have a video of the soapy water bubbling that I’ll try and attach.
Direct replacement was a JR Industry one.
Good job finding troubleshooting and locating the source. The old soapy bubble leak test is a gret tot find vapor lekas. 
I have a similar (if not the same) issue. Propane flows regardless of which tank is selected but neither direction shows “green” even though both tanks are full. The only time the “ glass” shows green is in the middle position between both tanks. Can you provide a part # for the direct replacement regulator? Also does anyone know how or from which tank the propane generator is plumbed?
The generator is connected the propane supply line that feeds the trailer. Stove, furnace and water heater a common header that supplies everything.
This is what I ordered
JR Products 07-31525 Compact Low… JR Products 07-31525 Compact Low Pressure Two-Stage Automatic Changeover Regulator, White: Amazon.com: Industrial & Scientific
