I have been using a workaround for symbolizing related records with versioned (not copied) Portal layers for a few years now. Basically this entails uploading your hydrant layer and maintenance table as a FL with editing for creating records, along with uploading a joined hydrant-table map image layer (MIL) in order to symbolize by inspected.
This works well enough for web maps and Collector. I have noticed that the symbology updating on the MIL is different in Field Maps. After creating a record that triggers a symbol, the symbol will update pretty quickly (within 10 seconds) on Collector, but on Field Maps it varies. It seems as though the layers do not update often. Even turning off/on layer or zooming out past visible extent. This is the same for editing existing or deleting a record that would take away the symbol. Both Collector and Field Maps seem to take a while for this. All of these things update very quickly on web maps. The refresh intervals are all blank or 0.
I am wondering if this issue exists within Field Maps or the Portal layer itself.
As far as I know, there is no other way to symbolize by related record without uploading a separate MIL for symbology.
I tested a SQL level view, which I had more issues working with in Portal.
Any advice? Thanks.