Thank you all, for your answers. I suspect that a cold transmission (after use) sucks the oil out of the dipstick tube. I over filled mine because I thought it was low. Now I need to remove some fluid.
On my Kubota B7800, when I first pull out the yellow plastic dip stick, the stick is dry. When I put the stick back in and remove it a second time, it shows overfilled. Is this a common problem with Kubota transmission dip sticks?