Haven't noticed an issue (and it seems like it's cloudy every time I go out to shoot birds). But I shoot only RAW, so I don't pay much attention to WB when shooting. Have you considered just setting the WB to cloudy, when it's cloudy?
I find the AWB on my 1DX is only confused by indoor lighting (so far!), everything else is fine virtually all the time. This is exactly the same as every other Canon digital camera I have owned/tried. I just use AWB and shoot in RAW - 99% of the time the WB is fine and on the odd occasion it gets it wrong it is a simple adjustment in pp.