When I was running hard doors I did have a problem with the driver door not wanting to lock or unlock easily. I cleaned and lubed the lock and it worked much better.
This is a problem with full doors only. Cleaning then won't really work. The Z bracket gets bent since there is too much movement between the bracket and the E-clip. I made a plastic washer and it really firms it up. The Z bracket doesn't rock anymore and pulls in both direction with no slop. The only problem is the key won't recenter in the up right position till it wears a little.
This has been an issue for years. Especially in the winter. When it gets cold the links stiffen up even with no grease and the Z bracket bends because of the slop at the E-clip. I've been locked out of my Jeep on several occasions where I couldn't open anything but the rear and had to climb in through the back.
I'm going to have to wait a few days to see how it holds up, but I think it will be fine. I have picts of what I did shortly.