OP,
Why does this,
I assumed she was joking, but no she's a very intelligent woman (double first) but she has deeply religious beliefs.
(something that I assume conflicts with your world view), lead to this?
Aibu to think this is a bit strange and to think less of her professionally?
Why does this lead to thinking less of the person in question rather than questioning your view of religion?
Why is something, that seems unusual / conflicting with a personally held world view, seen as a negative thing rather than positive?
Unless personally held views are things that are deemed as being particularly precious.
Mysteries are intriguing, entertaining and interesting...they lead us to question and find out more IMO.
I am a Christian, and for me this involves nothing as straightforward as a set of rules to live by. There are different, well reasoned (within the framework of examining traditions and Biblical interpretation) interpretations of what being a Christian means, which for me just strengthens my belief since I don't expect God to be easily and fully understood in this lifetime.