A report from about a week ago suggested that there were some Nintendo Switch owners who were not happy that they were experiencing poor WiFi signals on their device.
Nintendo is aware of the problem and already has a support document on its website that suggests several different ways that gamers can fix it.
However it seems that there are some new WiFi issues aside from this, that are bad enough to cause framerate drops in games. It looks like this has to do with the console’s WiFi “Auto Connect” feature. While searching for a WiFi point, it does so in such a way that it affects the CPU, which of course affects how games are being run. One problem leads to another and framerate is dropped.
That is why the framerate drops that are being reported are so inconsistent. Some gamers have suggested that disabling the feature could help prevent your CPU from being affected, but that is kind of inconvenient and not really a proper fix. This really should not be happening if the console was tested before release.
Nintendo is obviously aware of the issue and are working on a software patch that they want to include in their next firmware update, so hopefully this will fix the problem.