Volume vs Weight
If I were selling fuel, I would want to sell it by weight rather than by volume, i.e. I would be selling energy rather than gallons of liquid. In cold country, I wouldn't want to give away energy when the fuel was very dense.
I don't know how modern fuel delivery equipment works but, in the old days, fuel from the bowser was delivered by volume. When it got in the plane, the fuel gauges measured it in pounds. The crew monitored it on the gauges and when the required number of pounds were on board, they stopped fueling. It is possible that when fueling with hot fuel you might not be able to accommodate the volume of fuel needed in order to have enough energy in the tanks.