Not Cali only bikes. Mine is in the shop right now for same thing. And it doesn't matter if it sets in the sun when parked or not. The shop is scratching their heads as to how to fix it. If I knew it would never stumble in a corner or not start when I was a hundred miles from home I could live with just blurping the throttle on the 1st take off.
Yours sounds a little different. We're talking about ONLY right after startup - say for the first 1/2 mile or first 30 seconds to a minute after starting a bike parked in very hot ambient conditions. Clears itself up, then no more problems at all - once it's clear, you're golden until the next time you leave it parked in the hot. Unless it's >100 degrees F, my bike very, very rarely stumbles at takeoff or has hard starts and does not stumble at all once the initial 30-60 seconds of gargling clears (Except when I had a loose battery cable, but that's another story) - knocking wood now...