I have had a similar issue with my cruise control, not too frequent, though. For me, it refuses to engage around 20% of the time at the start of a trip, but once it's working, it doesn't give me trouble for the rest of the drive. Restarting the car seems to temporarily fix it.
I haven't made a special trip to the dealer for it either, but I am planning to bring it up during my next service visit. Maybe worth doing the same when you are already there for something else!