Hi there. I do not believe this problem is solved. I have tried the "solutions" offered and I still have the problem. The only "solution" that I have found is to turn smart lock off, unlock manuslly a couple times and turn smartlock location back on. Did I mention that I even tried "Trusted Devices" with the "Location" setting on. Nope. Invariably, I'll wake up the next day, manually unlock which is understandable and the next time I go for the phone the "Smart Lock" is not being very smart at all. Please, Somebody find a real solution.
That's strange that it works perfectly on my T-mobile GS9. I had the same issues as you up until a week or two ago when Google pushed an update specifically for that issue. Personally I would clear the current location entries and start fresh. I have two, one is a typed in address and the other GPS coordinates. I remember having to move it around on the Google map to get it right on top of my home and shrink that perimeter bubble down to my property. It hasn't failed even one time since the update. I hope you get the same results.