One car having a leaking evap system and other not could easily do that. I have sat cars for a couple years with ethanol fuel in them as long as evap seals, once you leak to aspire air in/out with temperature changes though you can count on water in the fuel.

By evap I mean any vapor control lines and tank seal at gas cap. All lines to carbon canister must not leak. Any leak close to fuel then leaches water into the ethanol in the fuel.

Take a gallon of fuel and put it in open container outside on a humid day, it will turn cloudy and have water droplets in it as soon as 5-10 minutes. I've done it a hundred times. The cloudiness is not dense, you will not see it at all looking into a shallow full fuel bowl. You generally don't see the water as well but you certainly feel the effect. The rust powder is evidence it's happening. That rust incidentally will manage to go by almost any filter on the planet, it is that fine. Most will go through jets harmlessly but it can seize up say power valve temporarily to make trouble as well. Problem comes and goes to drive you crazy.

95% of the carbs clogged and needing cleaning will look just fine looking inside the fuel bowl, it's in the dark passages and small orifices the problems begin. One could have a pile of that rust inside a vertical upleg easily since that would be a trap for it. Or trapped behind the transfers or idle needle tip.