I see multiple people in a specific girl's face, has this happened to anyone else?

So there's this girl, woman, female (whatever) who I've known for awhile and always had a crush on but we've never really gone anywhere. Recently, I've hung out with her into the hours of the night, generally talking and catching up (100% kosher). I currently am really diggin this girl. It's impossible to fully describe, but I'll say she's really pretty and challenges me intellectually/mentally---pretty much the ultimate brain-scrambling combo XD Dunno if that adds to the equation at all but it seems relevant enough to me . Back to the point of this question. One night I was hanging out with her seeing her pet duck (yeah, she's just awesome like that), and I looked over at her and I swear I saw another girl's face, one whom I've never had any romantic connection to. And in an instant, it was gone and back to her original face. It really bugged me out but I didn't mention it at the time. It kept happening again and again, and thus far I think I've seen upwards of ten different women in her face at different times, none of whom I'd seen that day or was thinking about. I've turned up NO results with the blanket google search, and am preemptively coining the term "polymorphic face" for the phenomenon.

Thoughts?

And for the record, I'm not taking any hallucinogenic drugs nor do I have a history of hallucination.