StrangeKeyStroke

Are you hitting the ctrl key by mistake? Possibly with num lock on.

If you accidentally touch ctrl and shift with more than one language installed on the computer then you would move around eg. US QWERTY, International, and Canadian French.

Settings → Time & Language → Language & Region → Keyboards
shows the exact list of languages Windows is cycling through on your computer.

If you don't require other languages then in Options allow only US QWERTY and inadvertent language change is precluded.

I don't recall the keystroke, but I once came up with a very young Fess Parker singing the ballad of Davy Crocket. I shut that one down, like very quickly.

seems harmless enough...

Harmless, yes. Desirable, no.

Speaking of which

Strange keys when I type, fingers do dances
Wandering when I type, what are the chances?
We'd be tearing hair whenever typing's due

Something that I clicked and led to switching
Something that I touched that caused the bitching
Something on my screen told me it's all effed too

Strange keys when I type
Two errant key tabs, there were strange keys when I type
Up to the moment when A2K said yo, little did I know
Fix was just a prance away, a warmness in my pants away and