Connection issues of both left and right Joy-Cons are a thing. And it seems Nintendo finally acknowledged that. CNET recently sent Nintendo a left Joy-Con that has connection issues for repair. After Nintendo sent the Joy-Con back, CNET opened it up to see how Nintendo did repair it. Apparently all it took was a small piece of conductive foam at the bottom right of the Joy-Con, which function apparently is to shield the antenna from interference. According to CNET, they haven't had any connection issues ever since. It is unknown if Nintendo is aware that the right Joy-Con has the same issue, but I can personally confirm that the right Joy-Con also suffers from disconnections.
Prior to this, a DIY video surfaced on youtube that shows how to fix the issue with soldering a small wire. Now even people without soldering skills can fix their Joy-Cons themselves. You just need a piece of conductive foam.
This is before the repair:
And this is after the repair (notice the bottom right):
Source
Prior to this, a DIY video surfaced on youtube that shows how to fix the issue with soldering a small wire. Now even people without soldering skills can fix their Joy-Cons themselves. You just need a piece of conductive foam.
This is before the repair:
And this is after the repair (notice the bottom right):
Source