According to https://superuser.com/questions/441608/my-keyboard-is-typing-by-itself-could-there-be-a-ghost-in-it I might have a faulty keyboard although their ghost key strokes look much more random than mine. But ... unplugging the keyboard and plugging back in did resolve the issue.
But ... WTH? Why would a keyboard store "TIL. Years." and print it out ... slowly ... whenever triggered a certain way? Why would there be a concept of pausing output for seconds?