"I've got an '07 38T also. Had a similar problem on day 1 with the passenger side slide lock. Been over 3 years, but I think it was a limit switch on the lock motor mechanism itself. A little tap and adjustment and it's been fine since then.
I believe it had to do with "driving the lock home" a bit too hard."
I had a problem with my slide locks too. I finally hit upon this idea: I would unlock the slide lock when I needed to put out the slide. Then I would "burp" it slightly toward lock.
By this I mean that I would push the switch for just a fraction of a second toward the lock position. This essentially would move the lock just slightly away from the full unlock position. This seems to do the trick. I have driven to Alaska and moved the rig, locking and unlocking the slides every day or two for over two months and I have not had the locks stick one single time!