My drivers side front one has been doing this ever since RC back in Oct. It was doing it a bit before that, but not as often. I did the same as you, silicone spray lube, washed it, etc. It never did it when it was raining or wet out because it would stay lubed. Now, this isn't a permanent fix, and I have no idea why it works for me, at least so far, but go out and loosen the bolts. Don't remove them, just break them loose and back them off a quarter inch or so. Then re-tighten them snugly, not super stupid tight, just snug them up good. It's basically cured mine. Still does it every once in a while but not nearly as bad. My theory is that I tweaked them when I went wheeling and when I loosened the bolt it relived the stress. Hope that made at least a shred of sense.