This is for our camper van / motorhome friends who have LPG tanks.
We found we couldn’t put any gas in. We knew from the monitor that it needed some but the pump thought it was already full. After phoning various people in England for advice the conclusion was that if the outside temperature is very hot (it was about 30 C) the temperature of the van’s tank is greater than the pump tank, so the pump thinks the van is full. We went into the mountains where it was 19C and could fill the tank with no problem.
So … if you have problems filling your LPG tank because of the heat either go up a mountain, or try early morning.