Field Parameter Stopped Working

I have a requirement to show a Column Header name based on the value of a column e.g.

Raw Data

To be shown as below:

I have created a field parameter as follow:

Due Param =

var _p=min(column1)

Return {(_p, NAMEOF(Column2),0)}

Although it was working fine before, it stopped working, I tried deleting/recreating /renaming but nothing works.

Kindly help.