Field order is being sorted alphabetically in the popup configuration when a feature service is added to the New Map Viewer. Is there a way to make the map viewer honor the original field ordering as shown in the feature table?
I'm running into the same thing involving inability to reorder fields in the New Map Viewer and have the desired order appear in Field Maps and/or Collector. Fortunately, I realized this early on so I did my field arrangements in Map Viewer Classic then saved over the map using the New Map Viewer and did the rest of my work using the New Viewer. This is definitely a big pain!