Puppy is awkward around older people

16 week Golden retriever, he is an angel really, just gets pretty awkward when i bring him to my grandmas house. Like he will full lay down and put his head down when she goes to pet him. he doesn’t freeze like he’s scared, just lays all the way down so im not really sure what to make of the behavior. We have exposed him to many older people since we’ve gotten him at places like his puppy socializing classes, lowe’s, and on no-leg walks.

Really just wondering how to approach his awkwardness with my grandma, do i give him treats when he sees her? do i give him treats when he lays down and she’s petting him?

he does lay down freeze when loud toddler come to pet him as well, also not sure how to approach that behavior