I was at a servo yesterday arvo and tried to fill the tank and it only took about 2 litres. A person using the same browser ( different hose

I then went onto another servo and tried again. This time I got another 4 litres in. The person behind the counter said a lot of people have had trouble filling today due to the hot weather.
Later that night ( 10 o clock ) I went to the servo and it filled without a problem

I was told that with the hot weather, when the car tank is almost empty what is left in it expands and when you attach the filler hose to it and try to fill it the nozel switches off because the tank has registered as full ??
But why can some people fill up and others cant ?
Very frustrating --- Any answers, or remedy's ????