Yup perfectly normal at that age for the reasons your spouse shared it is that 'shock/confusion' and at that age they only know how to express it any other way but to cry or get shy ... I have had even older children who look at me wide eyed like I have three heads if I bump into them out and about and will say things like 'why are you here? you go back to daycare' like I am some sort of zoo animal who is not allowed to leave that setting and seeing me in the store or what not is like seeing a giraffe strolling through

I had a 3 year old who I bumped into on a Saturday who just could not understand why I did not have all the other daycare kids in tow ... she grasped that while SHE got to spend time at her home in her mind everyone else lived at daycare and she was confused by the concept that no they all have homes just like you

The older they get and the more they grasp that people can be associated with more than one part of their life the easier it gets ... I have had 4-5 year old age group who be line through stores with excitement to see me out and about like they got a treat