Clarification on Doc ID 2091986.1 How Are Unsatisfied Relationships Determined

Dear  Primavera P6 Community Users,

I 'm studying P6 Professional and when reviewing the scheduling log using a SF relationship example I found out that the SF predecessor flags the following alert:

Activities with unsatisfied relationships........................1

Project: NEWPROJ-2 Activity: A1020 Actv.1020

A1020 as a SF predecessor which is being honored so far. However when A1020 starts, the log immediately flags it under the unsatisfied relationship section. No O-O-S event is being reported on the log. I'm scheduling using progress override. Also I'm not using any mandatory constraint that could override the logic.

When I try to read the solution the second criteria confuses me and I can't follow the business logic, i.e; from the document  ID 2091986.1 that explains the solution: