CR,
The lawyers just want you to be safe (and not sue Kubota.)
I bet yours in an HST model.
Mine is and did the same thing. In fact, it got worse to where it would not engage the starter all the time. Usually, it would "chatter." Turns out there is a safety switch (actually a pair) on your HST pedal which measure the "PARK" position of the pedal. These come out of the factory really tightened down to a tight regime where, once the pedal pivot gets a little dirty and the pedal isn't exactly in the center of the "zone" then, the minute the "butt" switch senses no one in the driver seat, it shuts off the motor to "save the chidren."
Make sense?
They adjusted mine at the dealer. I am thinking the switch is either on the pedal assy or just under the lower dash area. Open that range up a bunch and you should solve your problem. Good news is, I can move my tractor in idle at a very very slow speed by moving the pedal (The crowd "GASPS!") but that makes slinging loads a heck of a lot easier if your machine needs to move forward 6 inches. Your mileage may vary. Just sayin'.
Good luck!