As an aside, I went through a few mental gymnastics to think maybe putting your joycons in backwards, so if you're wondering - no, putting your joycons in backwards doesn't work.
Yeah, I think OP's was an accident - one time bugs that can't be reproduced happen here and there. Most likely that.
I do believe that this would be an easter egg in the system though. It's a bit of work for something unreleased, and it's hardcoded into the system.
Er, you sure about that? I can see the X if I squint, so I believe that, but it still looks like X Y B RightStick to me...
EDIT: Though, If I have to be honest, having B be the last stroke would make more sense, considering B=Back=out of menu
I feel like school, back when I was actually in school, was more entertaining though, because of how much I get to interact with people, hang out with friends, and other stuff like that. All I get to talk to at work is my boring coworkers lol