I had a similar issue some time back, I had a large volume of fuel become jellified and was pretty annoyed as it wasn’t cheap so ended up speaking with a petroleum chemist from our supplier.
He told me that the fuel composition is changed between summer and winter months. Apparently they use a mix to ensure the fuel remains liquid in winter and in summer they change it so it doesn’t loose important characteristics through evaporation. He said the mix was gradually changed through the shoulder months.
I don’t know what they do in the warmer parts of the country but perhaps it could just be that it is “summer mix” and you’re experiencing a colder period?
Frosts are not unusual here and our fuel storage was on the south side of a shed shaded by some big stringybarks The bloke told me to fill a container and place it in a warmer position and it would be fine to use once liquid again. Getting it into the jerrycan was a bit of a challenge but he was right, things ran just fine with it too.
