I wasn't sure if you Dad had actually spilled any, this one is noted as not spilling any and it went up, and it sounded like the same thing.
I was having some issue on the one section of my property, I dropped the air pressure to 10 psi in the rears and 14 psi in the fronts, and also filled only half a tank of fuel, have that single 5.5 tank on mine.
That is a brand new post which sounded like vapor or something.
I don't have to refuel on my property, but for sure after seeing 2 won't take any chances.
The air pressure adjustment worked pretty well, and I switched it up a while back to waiting atleast a full day for it to.be dry with no dew on the grass. It's pretty sketchy and when it looses traction it's a ride till it grabs again.
The half tank of gas means nothing it's like 20 lb, I figure the dry weight is 1200, plus me 200, plus fuel at 8lb a gallon 40. Was easier then me trying to go on a diet and drop 20lb. So I'm at 1420, the thing is a heavy set up.
Couple other issues I found if your going to so slopes once you point the nose to the left it's hard to recover from that, cheat the front end of the machine to the uphill side at all time, make sure you have more uphill throttle then downhill throttle so it's skewed to the uphill slightly with the fronts.
Obviously no Turing on hills and try a different approach.
If all else fails I just don't cut that small area with this machine. It's only like 3 passes that I have an issue doing.