It's all good. I appreciate your response and I am glad I was able to find a workaround. Unfortunately, Field Maps has the same "bug" that the new Collector (not the Collector Classic version) and Explorer apps (after v.18.1.0) has that makes the app essentially unusable. All three apps have a variation of the same error message. This is when we sign in to the app with our Portal logins and does not apply to AGOL.
In Field Maps, if I open up the layer list for a map, under each layer name, it says "Token Required" and it can't load any of the data. In Explorer, it used to say "User cancelled the authentication challenge", but with the latest version of the app, it just keeps on taking me to the Portal sign in page when I open a map. No matter how many times I enter my credentials, it just keeps on asking me for them over and over again. Eventually, if I click the X button to close the sign page enough times, it gives me an error message for each layer saying "super.handleChallenge(challenge) must not be null." I made a Geonet post when I originally reported the problem (Explorer for ArcGIS Error - User Cancelled Authentication Challenge). I also opened a case with Esri support.
I was told back awhile back from Esri that it should be fixed around now. I was really hoping that Field Maps would include this fix, but it does not. So we're still stuck with sideloading an old version of Explorer and Collector Classic until it gets fixed.
Since this is with Field Maps, I can open up another support ticket with Esri, but I don't want to be that guy who continuously submits bug reports for the same issue.