I just had the actuator replaced on my rear door. It seems at least once a year one of these needs replacing. Mine was running with the door open. Keep in mind these go frequently which supports the software update on reducing wear and tear.
2012 535xi|Dark Graphite|Black Interior|M-Sport|
Prior BMW's: 1987 325e|1993 740i|1998 740il|2002 745li|2007 750li|2006 750li