Related Data will not appear or is incorrect when connected to a feature service.

[Tony_J_Van_Der_Wielen]

We are doing culvert collection, inspections, and maintenance. We have a point feature class that has two related tables in Oracle. Field work seems to be working fine, but when connected to the live feature service (10.9.1) the related data will not show or will not show correctly in a map, app or pro. Connections directly to the data in ArcGIS Pro look good, and when a replica is made on an iPad the data also looks good. It seems when connecting to the live feature service the data is not displaying or is displaying wrong table information. We have had a ticket open for months, but I wanted to see if anyone is having a similar experience.

[clt_cabq]

How are you publishing your feature service and related table? I've found that if you have a geodatabase (such as an enterprise geodatabase) with built in relates and you are publishing through enterprise or ArcGIS Server that those relates seem to be ignored when you start working with them in AGOL (and probably Portal too). If you have your data in a fgdb, establish the relate there and then publish the data as a hosted service in AGOL that relationship will work however. Its very frustrating and when I've asked ESRI about it they have nothing useful about when they might fix this issue. You can fuss around with arcade get related information into a popup using a filter operation, what i have referred to jokingly as a "poor man's relate" but it won't show you related information in table views and such. 

[Tony_J_Van_Der_Wielen]

We have relationship classes built in the enterprise geodatabase (Oracle). Publishing is done through ArcGIS Server (10.9.1). The interesting part of this issue is this has been working fine for over 3 years. We started having issues in December 23/ January 24.