A final rule conflict arises if a rule is marked final but rules with that same name also exist in other rulesets. This rare situation can arise when rulesets are uploaded with the Import landing page tab
You can find final rules that have both the same name and other visible key parts by using the Final Conflicts report Rule-.ListThisRuleFinalCollisions.ALL. Eliminate any conflicts by deleting one of each conflicting pair until this report is empty. To access this report, select Designer Studio> Application > Inventory > Inventory Reports. Select Rule as the Category and enter "final" as the Search Text.
Custom rulesets will take precedence on Pega ones by design.
Now this is a good finding, why is this activity customized? Did you solved an issue which is now included on the new version of this Pega activity? If yes then maybe your activity could be withdrawn now.
Also if the activity has been set to FINAL maybe customizing it wasn't the best design approach in first place.
All that to say that I believe scenarios could be very different from a rule to another, forcing or blocking arbitrarily might not be a good approach either way.
This activity was modified in earlier version of Pega to meet specific Business Requirements. Now in the latest Pega version, the same has been made final. Out of curiosity, I tried saving the final version of rules in our custom ruleset and I still could override these rules even if they are marked as Final in the latest Pega release. I was just curious to know if Pega should really allow these rules to be overridden now if they are already marked as Final?
I am already in touch with Steve Williamson who is our Pega Service Advisor. He is aware of the issue & he is helping us out. If required & when he confirms, we will raise SR on this. I will keep you posted on the further updates.