DSF saying 4 month olds flirts

[LLOE7]

My DSF (step father) has said a few times to my 4 month old dd "look at you giving it the big eyes, you're flirting with me aren't you!" When she smiles at him. I've always ignored it as I know it's harmless but it's not sitting right with me. Today we went to the vets and my dd smiled at him to which he said to the receptionist "she's always flirting with me now" and then turned and said to dd "you shouldn't be flirting with ME- I'm your grandad!". This made me feel so uncomfortable and a bit embarrassed as the receptionist raised her eyebrow and gave an awkward smile. Is this just something that's said, or am I right in thinking it's a bit weird?
WIBU to tell him to stop?

Shocked at the responses here. This is a hugely common thing to say about babies where I'm from and nobody would think anything of it. Surely if there was any underlying intentions he wouldn't be broadcasting this out loud? Sounds completely innocent to me. If you don't like it, you'll have to say something as clearly he thinks it's fine to say.

@rosieeffect read the thread please, op has suffered horrible abuse by her parents and no his comments are not normal.
Are you suggesting most people say "you can't flirt with me I am your grandad" is normal?
Because it isn't.

Apologies, I did miss the part about op suffering abuse.

But yeah, the part about 'you shouldn't be flirting with me bc I'm your grandad' does sound normal and innocent to me. I suppose it depends on where you're from and you're experiences but my initial reaction to people who think otherwise is 'get your mind out of the gutter'.

Rosie - I agreed with you until I read the update. You might not have seen this so please read it. It’s shocking, and sad.

Yuck! I wouldn't leave her alone with him, ever, but my step-grandfather abused me, so maybe I'm slightly triggered by this.

Eugh. He needs to be told that's inappropriate & if he 'doesn't know' why, explain.