A stranger bought something off my registry?

I'm definitely overthinking this but I saw today that someone bought 2 items on our registry that I'm super excited for! Clicked on the thank you list--it's a name and address I've never heard of before. Checked with family and friends who live close, none of them know either. This happen to anyone? I feel so shallow pondering over this and maybe it's my OCD really nagging at me...suggestions?