I think there were two balljoint issues a while back.
One was where they were installed without paying attention to the index arrows that are supposed to be lined up which caused binding during use.
The other one was Asian replacement balljoints that would become stressed somehow when assembled to the trailing arms and then would bind and be stiff. I think @chines1 Carey Hines had a few of those and alerted us to them. IIRC, if you got Brazilian VARGA units they were OK. And, of course, the German ones have always been good.