Bronica SQ Lens release

I was in the field today starting to take some pictures with the 80mm lens on the SQ switched to the 50mm wide angle but didn’t like what I saw and started to switch back to the 80. But couldn‘t get the lens to release. Fortunately I was within walking distance of my house and gave up and came home, lost the light anyway . It was only about 50 degrees and I have used the camera in much colder climates. Checked every thing out including a new battery but had a devil of a time getting the lens mount to rotate and release the lens The shutter was cocked. I waited until the camera was warm and it finally it released, with much effort .When I examined the lens mount on the camera the grove is dry with faint signs of scraping. Is this suppose to be lubed somehow? Or is that mount that susceptible to the cold.?