You could try to replicate my setup. Add all three URIs:
As the Firefox is more my test system, my match detection default was on “Base domain”. I added the URIs with “default match detection”, so if you think about it, you could critize that setup here. 
But would be interesting to know, if that would make a difference for you.
(generally, I tend to add all domains and relevant subdomains… so that if I change to e.g. “Host” as default match detection, autofill doesn’t break down )