I bought my 5D MK III in early June. I haven't shot a ton of stuff yet - maybe about 2000 frames over 7 or 8 sessions. But in 3 or 4 of those sessions, AF just quit. Anyone else seeing this anomaly?
Is this phenomenon happening with just one lens? Or across different lenses? It may not be the body at all.
I have a 20K plus actuations 5D3 with no AF problems so far. Mind you I did have the shutter replaced at around 2K actuations but this is irrelevant to the AF matter you have described.