I spoke with the analyst who owned this case and I was able to get a copy of the data. I found that I could only reproduce the issue with the 9 records in Vernon being geocoded to two locations when I did not manually map the Licensed Locations field as the address field. This must be done manually because the geocoding dialog does not do it automatically. The fields that were mapped automatically were City, State, Zip and Zip4.
My testing involved publishing two services with this data, one with the address field mapped and one without. What I found was that when the address field was not mapped and there were two locations for Vernon there were 8 records at one point and 1 at the other point. These were based on zip code.
With both feature layers added to a map I got a better idea of how close to accurate the points were located without an address. In some situations, the locator matched without the address which is pretty impressive. In other cases, it got very close because it located down to the 4 digit zip extension.
If we look at the locations in Pro using the locate pane we can see detailed information down to what level the location matched. This is noted in the AddrType field. When the address is provided it matches down to AddrType: PointAddress and if it is not provided it matched down to AddrType:PostalExt which is still very precise.
Here is a video demonstrating how you can see that information.
I want you to feel confident that the World Geocoding Service is extremely reliable and accurate. You have my email, please feel free to reach out if you have any further questions.