Can someone explain how the Segment filtering order works

Your software
My Mautic version is: 2.16.2
My PHP version is: 7.2.30

Your problem
My problem is: we are having a hard time understanding the Segment Filtering UI. We can’t find documentation on the topic anywhere. Given the image below:

What is the final filter?
(Registration Source in (..., ...) and Last Login Date < '2020-01-02') or (Registration Source is empty)

(Registration Source in (..., ...) or Registration Source is empty) and Last Login Date < '2020-01-02'

By the way, we are trying to accomplish the second option.

Can you point us to documentation or blog post on how this works?

These errors are showing in the log: N/A

Steps I have tried to fix the problem: N/A