Hi,
May be theses images will tell the issue.
-Addresses {Business Object}
--Attribute-> Suburb {Reference Business Object display as Drop Down}
In this Image below, Attribute Suburb is working nicely when Addresses are Added as Add New Action.
Where Addresses is a reference attribute of ClientUser Business Object
-ClientUser {Business Object}
--Attribute -> Addresses {Reference Business Object display as Table Of Items} Multiple

DISPLAY IN A POPUP VIA ADD NEW
And, In this Image below, another Business Object BusinessUnit has single reference attribute Addresses and display as form on the Parent Object Form. Here, Suburb field in the Addresses form when clicked custom template is not showing the other values of suburb.

DISPLAY AS A FORM IN A OBJECT FORM
Please let me know if anything to ask.
Thanks,
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