Thank you for your reply Peter.

In my case, I also let the fueling stop when the pump "pops" to stop. I do not top off.

I suppose the pump I used could have allowed excess fuel to enter my tank, although I've used this particular Chevron before and have not had this issue before.

The temperature was approximately 55 degrees celcius at the pump, but in my garage it was probably close to 60. Not much of a difference. But I can see what you mean if the gas expanded or contracted.

I'll see if the noise happens again. Hopefully it was just a fluke!