I just tried the Phone app by Google. That's what I thought I was using but I guess I wasn't. I think I was using the built-in OnePlus Phone app but I'm not for sure. I couldn't find information about the app anywhere to verify who developed it. It doesn't even show up in the app list in my phone settings menu, which adds to the argument that the app is probably baked-in to the phone (of which I have a OnePlus phone).
I tried the Google Phone app a little bit. It seems to do a better job of finding matching contacts than the OnePlus Phone app but it's still a bit hit and miss. Sometimes it won't find a matching phone number unless you type the whole number or even the 1 at the beginning (to indicate a USA phone number). OnePlus's app is even fussier than the Google one but both seem pretty lazy. I'll have to play around with it some more. I suspect that OnePlus didn't take a lot of time to polish some of their apps and left out some features, or at least moreso than Google did.
I appreciate your help.