This has been an ongoing problem for quite some time... search the archives.
I have had the same problem with my 09 cruiser 30sk. Have had to dealer(s) several time for adjustment to no avail. As you say move it manually a bit & it works fine. Also discovered that if the BELL stopper is backed off slightly form the frame all is well for that time only. Have broken the manual rod 2x so now carry a large pipe wrench to back off the bell stopper just in case.
I wonder if the slide is just too heavy for the mechanism ie. the motor
2007 chevy crewcab D/A
2009 Cruiser 30sk