The actuator might be the problem,
it is the one who gives electrical signal to run the pump (either vacuum or pressure) to close or open all the doors..if signal OK, the pump will start working->if there is a leak - which is also could be from the inside of the actuator - the pump will run longer anfd there will be delay in locking or unlocking all the doors.
the actuator about $49 or so, it is sealed as a vacuum unit and it has an internal electric switch...it can leak and the switch can also fail sometimes...
Hope this will help