One problem related to ball joint has been reported for the 2014 Tesla Model S. The most recently reported issues are listed below.
The left front fore link ball joint snapped like glass during normal driving. Luckily I was going at relatively low speed on a side street. This allowed the suspension to allow the wheel to slam into the firewall and it locked up causing the right side of the vehicle to hit a curb. As an engineer this scares the daylights out of me, as if it would have happened on a high speed highway turn, the results could have been deadly. Even without an understanding of advanced metallurgy, it's clear that a hardened steel ball joint should be stronger then the surrounding aluminum alloy parts on either side that it attaches to. It looks like a glass rod hit with a hammer. This same thing happened to another 2014 in our family about a year ago, and I chalked it up to random failure. But now 2 failures? I have the original failed part if needed for analysis. The replacement part I obtained through Tesla has been re-engineered, and appears to be from a different supplier. I went ahead and replaced both sides, and I still have the non-failed part on the left side. I attempted to contact Tesla about this, and they have not responded to me.