It does it to all games? If so then i'm assuming that it's either a coincidence that this happens with the games or that it's something custom to the dsixl itself.
Don't argue with idiots because they will drag you down to their level and then beat you with experience.
That's assertedly the soft reset key combination for DSi. Is it bad? No; it's merely supposed to restart your game card while keeping the power on. (From what I read, useful for saving time while catching shiny Pokemon.)
However: I've tried this numerous times on my own DSi and never once got it to happen, but for an XL, I wouldn't know.
I think the original DS had a slightly different key combination than the later models. Then again, it may have been easier, as opposed to more efficient, to just press the home/power button on a DSi/XL. Brings to mind the 3DS, which has no known traditional soft reset, but supposedly the standard DS reset will work while it's running a DS game.