There's always a new way to make a mistake.
Yesterday I managed to yank a film holder out by its half pulled dark slide because it bent up against the tripod and bound in the holder. I was shooting in the snow with the dark cloth tented over the whole camera, so I pulled the slide down and normally I don't do that on verticals.
When you find a good routine, repeat it if possible. If you do something slightly different, expect it might screw up in some unforeseeable fashion.