It's obviously a glitch.
It can be either your system or your game. Your online settings are fine, the lights probably just stayed on after turning off because of the console.
You can try get another 3DS somehow, and if the effects fade, then it's your console that's the problem. Of course, replace. If the effects remain, obviously, replace the game.
So... yeah.
Hope I helped. :)
Source: Common sense. xD