I can see how that would be super annoying
I do have a few suggestions. You can start by making sure your e911 address is updated using the steps on our Change your billing and e911 address page.
Testing another Wi-Fi connection will tells us if this is something coming from your phone or that one Wi-Fi signal.
You mentioned some concerns with lollipop however our LG G3 page shows marshmallow is available and includes improvements with Wi-Fi calling. Having the most recent software should help.
If you want to continue using this or if you decide you want to get a G4, I'd just like to help you get the Wi-Fi calling working. I suggest giving the steps above a shot, and if you do, please let us know if the Wi-Fi calling improves.
Thanks for posting.
Did any of the suggestions that Mike mentioned work for you? Did you end up switching phones or staying with your G3?