Thanks. Worked late tonight and then had a meal before getting started with the mowing. It was already dark when I fired up the Kubota. A few years ago my work schedule and weather dictated mowing when the grass was high and dry. It was well into the mowing season before mowing very much without lights.
It's brighter around the tractor than the picture shows. I think the one LED tricked the shutter into thinking it was time to close.