Fuel Tank Issue

[Rv12]

Has anyone had problems with crossover tube not working on Supernova 6400? Just ran out of fuel on the highway with 70 gallons of fuel in the left tank. Was able to place some fuel in the right tank, bleed the fuel canister and start the truck to make it to the next gas station to get diesel fuel. The RV ran out of fuel with 70 gallons of diesel fuel in the left tank...and we were only 40 miles away from home after traveling 2200 miles. Fortunately we ran out of fuel in the right tank on a beautiful night with cell coverage, but the shoulder was very narrow and the cars and trucks were blazing past us in excess of 75 miles an hour. Fortunately the hazard lights and triangles we placed behind the RV prevented us from being ran into. Taking the RV to the shop next week to be repaired, but just curious if anyone else has had this same problem. We love the RV, but running out of fuel with 70 gallons of fuel in the left tank was very unexpected. Looking forward to any advice or comments. Thanks.