Norcold 1210 with replacement cooling unit propane blows out on the road

 Fridge stopped working last year. Replaced the cooling unit with the unit from JC Refrigeration. It works fine on both electricity and propane but on propane for rolling down the road it stops working. Once stopped, power off/on gets it working fine again. Blows out??

Any ideas why it stops working? Yes, I know the propane hose is disconnected in the photo - I replaced it because it was cracked and leaking.