Is Equipment::ItemName the field that is appearing blank in the portal row?
Is it a text field or a calculation field?
This isn't typical behavior for a text field, but there are cases where a calculation field may fail to evaluate or display correctly until the window is refreshed.
Equipment::ItemName is a text field, other fields do not appear straight away either in the portal row such as Manufacturer, Model Number etc...the _fkEquipmentId always appears but the following information pertaining to that record does not. After a few minutes playing around in other layouts and Manage > Database then it seems to appear. I do have a few scripts none of them tied to buttons or related to portals though.
Try creating a brand new layout based on Clients. Give it a brand new portal based on ClientEquipmentJoin. Add the fields to it. Do not copy any objects from the original layout to paste into this layout.
Do you get the same behavior?
I deleted the join table and created a new one, seems to have fixed the problem! Maybe a problem with fields on the join table. Strange behavior, thanks for your help.