I don’t think you need to be concerned. Mine is just starting to do it more consistently and is doing it sometimes by command without help now. I’m not sure if it helps with you doing it all day because you’re around and not actually coming or going away from them..? What I did was had family video calls and then show and say wave 👋 hello and wave 👋goodbye and then the family members do it too everyday. Also, practicing when going to or leaving daycare or around other people. Mine tends to be shy with strangers too so family is good for learning.
My son is 16 months and is the same! I don’t think it’s anything to worry about