There appears to be a way to fix reported connectivity issues with the Left Joy-Con Switch controller, which is causing erratic game actions, or even a complete disconnect.

YouTuber Spawn Wave recently posted a video showing why he believed the left controller suffered more so than the right. His Joy-Con tear down revealed the right controller has a wireless antenna attached via a cable, whereas the left controller's antenna is built into the circuit board. This in itself isn't necessarily an issue, but the inability to move the antenna away from a metal plate could well be a big problem.

Spawn Wave has now posted a follow-up video in which he solders a small wire onto the Left Joy-Con circuit board to act as an antenna. This allows for placement away from the metal plate.

The results are hugely positive, with the Left Joy-Con actually out-ranging the Right by a considerable distance.

Although a simple fix, you really shouldn't attempt something like this yourself unless you have experience and don't mind if you end up breaking the controller.

It remains to be seen if Nintendo will be forced to take action regarding the Left Joy-Con issues.