Your brain just confidently walked up to a total stranger and said "I know you from somewhere" like it had any idea what it was talking about. Spoiler: it did not.
This happens more than people realize. You lock eyes with someone across a coffee shop, and suddenly your brain is flipping through its mental rolodex like a panicked librarian. Was it high school? A work thing? A dream? A past life in medieval France? The possibilities are endless and all of them are wrong.