Value set Providing different results each time in Payroll Input Validation Formula

Summary:

I am using a fast formula (Payroll Input Validation) to call a Table Value set where a sql is ran to check the logged in user role.
I have attached the formula to a element at the element level as a Validation Formula.

It produces different results each time for the same user for the same element entry on the same date.

I tried hard coding a value in the Table Value set using a dual and it still produces varing results.

I have outputed the value set variable into the error message so I can see what is happening.