I can't really find some good documentation on how this actually works. I do know that there are no rules that Status (17 "Lead | Non-Lead", "Unknown | Lead", etc.) is based on actual material type. If the utility or service determines the preset Status field, then you should have a rule that if you enter or auto-populate the material from existing GIS data or the actual inventory process, that the Status is changed as well. Currently, you can easily make bad data in the status field if material is changed. I would suggest a schema change, Rule or Arcade code that will make the Status mapped from the value the pipe material is set, to maintain the accuracy of the pre-set Status fields.
Thank you for the suggestion. We did consider this at the time of development but decided not to add it for a few reasons:
This is something we can explore moving forward as Web AppBuilder and Experience Builder get closer parity.
In the meantime, you can try adding form calculations to the Field Map to populate the Status fields using the material fields. You can also try the same for the Lead Service Line Editor map in Map Viewer (not Classic), although I would try this in a copy of the map as I am not sure how this may impact the map and WebApp. Below is documentation for setting form calculations in Field Maps and Map Viewer.
Field Maps (Add calculated expressions section): https://doc.arcgis.com/en/field-maps/ios/help/configure-the-form.htm#ESRI_SECTION1_ECDC6C18501D440AA...
Map Viewer: https://doc.arcgis.com/en/arcgis-online/create-maps/create-form-mv.htm