Oil droplets in plenum

I have a 2011 Ram 1500 with a 5.7 Hemi. It was running a little rough and one of the steps I took was to clean the throttle body. I removed the throttle body and in the manifold plenum chamber directly below the throttle body there were droplets of what seems to be oil. Isn’t the chamber supposed to be dry? Has anyone out there experienced this same issue and what was the source and remedy?