One of the problems that has effected the launch of the Nintendo Switch was a persistent connection issue with certain Joy-Cons. For a number of folks, the left Joy-Con would disconnect or the signal strength wasn't up to snuff. Folks tried to figure out why this was the case, but in the end, no single cause seemed to cover what looked like a hardware lottery.
Nintendo's previous guidance was that users should keep the Joy-Cons and Switch system away from sources of interference, including smartphones, internet routers, and aquariums. The problem was that some were still having issues outside of those situations.
CNET sent one of their faulty Joy-Cons into Nintendo for a fix and when they received the new unit, they promptly opened it up to see what was changed. Surprisingly, not much. The biggest change was a small piece of conductive foam, sitting near the antenna. CNET removed the foam as a test and the Joy-Con connection issue returned, so it seems Nintendo has found a fix for the intermittent hardware issue.
That was confirmed by a new statement from Nintendo, calling the Joy-Con connection issue a "manufacturing variation".
"There is no design issue with the Joy-Con controllers, and no widespread proactive repair or replacement effort is underway. A manufacturing variation has resulted in wireless interference with a small number of the left Joy-Con. Moving forward this will not be an issue, as the manufacturing variation has been addressed and corrected at the factory level," Nintendo told Kotaku.
"We have determined a simple fix can be made to any affected Joy-Con to improve connectivity," the company added. "There are other reasons consumers may be experiencing wireless interference. We are asking consumers to contact our customer support team so we can help them determine if a repair is necessary. If it is, consumers can send their controller directly to Nintendo for the adjustment, free of charge, with an anticipated quick return of less than a week. Repair timing may vary by region."
So the mystery is solved, it seems. There were Joy-Con issues and they were due to a small hardware problem. Glad Nintendo got there eventually.