Since yesterday's embargo lifted on the Nintendo Switch there have been several reports of the Joy-Cons desyncing from the Nintendo Switch during gameplay. We can confirm this has also happened to us while playing The Legend of Zelda: Breath of the Wild while in TV mode, while we were sitting about two meters from the TV.
At times we noted some lag issues, with the controller not responding immediately to an input, or losing response for a second or so, but in a single night the Left Joy-Con lost connection on at least four occasions. This only happened while playing on TV mode, and we had no problems with the Joy-Cons inserted on the Switch in handheld mode, or playing close to the device in stationary mode.
This is obviously a major issue, so let's hope Nintendo can fix it using a console update before the Nintendo Switch actually launches on March 3.