L. discolor shows no sexual dimorphism. Flowers are perfect so self pollination is possible. It's unlikely that a gnat did the deed, but a bee or fly could have.
All Jewel orchis don't do this for the same reason all orchids dont do it. The pollinia making it to the stigma is pretty huge. If you don't do it yourself, what are the chances? I have lots of orchids that bloom all the time, but never set seed.