Have your goats been tested for CAE? I have been raising AGS & ADGA goats for 8 years now and mine rarely graze on their knees, but mine are CAE and CL negative. While nursing, yes because it's easier to reach moms udder, but just grazing like in a pasture, most goats never eat graze like that unless their is an issue. Now yes, mine do occasionally eat like that when they are surrounding a hay bale, but grazing no, and they don't do it often and shouldn't.
I've spent most my life riding horses...the rest i've just wasted.