This is what I shared on Twitter a few days ago.
Sound emulation bug when the burn-in protection triggers. It seems to happen with every #NES game. #NintendoSwitch pic.twitter.com/xYbZLtuUeM
— Link-NM (@Link_NM) October 3, 2018
Since this was recorded through the Switch, though, you can’t really see when the burn-in protection triggers. So here’s a video of the bug but recorded through a capture card, where you can clearly see (and more easily hear) the glitch that I’m talking about.
The glitch was partially fixed on the current version which was released recently (October 10, 2018). There’s still some sound distortion but it’s now very hard to notice it.