Interesting. Are there any other accounts on your phone that provide contacts? Maybe social media or other chat platforms? On Android you can see accounts in Settings > Passwords & Accounts (or somewhere similar; it varies a little between brands). You can also check inside your Contacts app by expanding the sidebar (again, varies by brand).
Just a thought. I don’t have any other contact providers on my phone so I can’t test it myself.
Please keep us posted if you get any official response or learn anything new!