Relations dosent work from Collector

[Lars_EngelsbyMosbech]

Hi,
We have created a ArcGIS Server 10.6 feature service. Under the server there is a postgres database. We have serveral relations that work very well in the database. All is set up to work with Collector app through Portal.

However. One of our relations dosent seem to work. As attachment shows, there is a 1:Many relation between the tables sensor locations and  images of sensor locations. The image table has attachements enabled.

When a new record is created in Collector for ArcGIS, the UI in Collector tells me that everything went well, but when i look in the database, it dosent automatically create the parentguid (see attached image).

Any idea why this is happening?

It works if create the records through the same service but using a Web App Builder app instead..

[Lars_EngelsbyMosbech]

Found a solution: In turns out our Postgres database only accepts lower case field names. So when we established the database it made all field names lower case. However the relations where still with upper case. 

Then funny thing (and something for Esri to look at) is that the the issue of relations with upper case field names (ParentGUID) and db with lower case field names (parentguid) works from a Web App Builder app - but not for Collector for ArcGIS.

I have now deleted all old relations and created new ones (with correct lower case field names) and republished services..