I have a feature service with a couple of layers and several tables, and a few relationships between all of them. I have apps built off of this so that a polygon can be selected and Feature Info populated with logic from related records. I just happened to be attempting to show the app off to the heads of a different department at work when the related records displayed as unavailable. Every relationship that I reference in a pop-up returns "No records were found"
I looked at the data in the Overview page and the REST endpoint. All of the data is there, and the layers/tables still show that they have relationships.
For added context, I've used @Clubdebambos' code from this thread to add relationships programmatically in the past. Solved: Adding Relationship Class to Featue Service - Esri Community
I've also used his code from Final Draft Mapping to add tables; I ran into an issue where the tables didn't display in the AGOL UI even though I could see them in the REST pages. I ended up solving that with this snippet:
item.update(data={
"layers": [dict(layer.properties) for layer in flc.layers],
"tables": [dict(table.properties) for table in flc.tables]
})Solved: Re: Added Table to Feature Service - But It Doesn'... - Esri Community