Ref Tables

[cypills]

It Seems, i have forgotten to to ref tables in the Columns Sections.
I have multiple Tables and the unigue field or headers in all the tables is ITEMCODE.
For eg. Table for Warranty, Table for Specs Sheet, Table for Stock. All these tables have one Unique Field called ITEM CODE.
I have been to Data >> Columns>> Select Ref for the required Header but still the Sheet does not pick up the required reference data from the other tables.
Previously it used to work by showing a BLUE > mark besides the text, now it shows a Yellow Triangle.
Can you please help.

[Aleksi]

Any chance that you have changed the key column in your parent table? That could explain the broken reference (yellow triangle).