The Nintendo Switch is currently out for certain people, and along with that, there have been reports about the left Joy-Con controller not syncing properly. That might not be the only problem people might run into if they are not paying attention when putting the wrist grips on.
The wrist grips have a plus and minus symbol, so users just have to match them up properly and slide them it on. As shown in the video by The Know, Burnie Burns of Rooster Teeth puts the wrist grips on backwards, where the symbols did not match up.
The piece seemingly went on with little to no resistance, with Burnie even saying that he had no problem putting it on that way. When it came to removing the wrist grip is when the problem occurred, you can see him trying to remove it with nothing happening. The video does cut while they to remove it, and does come back right before they successfully do so. While that is a good sign that you could fix it if you do it improperly, it should be noted how easy it was to put the wrist grips for the Nintendo Switch on the wrong way and how long it took to fix it.