How does the system choose the Area of ​​Responsibility representative to assign workflow approvals?

Hello, I have the following use case:

Two people (A and B) have the same responsibility as Payroll Representative to act in the approval flows. With identical scopes to serve the same audience.

But all approvals are always intended for person A and never for person B.

The understanding we have is that this choice is made randomly with the execution of the internal SQL that returns the members of that area of ​​responsibility. But of all the tests I've done, the flow is always destined for the same person.

Everything is fine with person B. The only time I was able to simulate the approval being intended for her was when I set an end period for person A's responsibility, so person B received it.