Behavior > Action > Behavior > Only if condition

Greetings!
I am having difficulty in setting up the expression for the said condition in my subject.
I am trying to hide base on the column value of table of this system generated action. The problem is when I put the expression:
ISBLANK([request_id])
it returns TRUE, and thus action display.
But the column has a value and I also perform a test of the expression in which it returns N which proves it has a value. Why is this happening?
I can provide more explanation if needed.

Can you show more about where and how you are using this and maybe a screenshot?