Hot weather, low fuel, big whoosh. Sounds perfectly normal.
Think of all that lovely sunshine expanding those fuel vapours and then you let them out.
Don't fret.
But more importantly, while this fine weather continues, avoid filling your tank then just leaving it in the sun as there's even less space for those vapours to expand into.
If you're gonna fill it, do it before a big ride.
Got a garage or shady storage? Ignore everything I've said above (apart from the "don't fret" part)