Mystery pollinator

[euplusia]

Some Cattleyas are self-pollinating, for example those with Guarianthe aurantiaca in their ancestry. Actually Guarianthe Guatemalensis produces a pod in my collection.

On the other hand I often see bumblebees in my greenhouse. They come in because it is warm there, and stay for the night. They especially prefer to crawl into the flowers of large flowered Cattleyas, where they sit protected by the lip to their sides, and sheltered by the column over their back. In this 'bed' they sleep. The next morning I find them exhausted and with pollinia on their back. Actually they made Cattleya intermedia flowers to fade too early.
I think some sort of insect is the most likely reason for the pod of your Cattleya.