I believe the text of the "agenda groups for rules" does not match the example on the order of execution of the agenda groups. 

https://docs.drools.org/8.44.0.Final/drools-docs/drools/rule-engine/index.html#_agenda_groups_for_rules

existing text with comments inline in blue.

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For this example, the rules in the "report" (should be "calculation") agenda group must always be executed first and the rules in the "calculation" (should be "report") agenda group must always be executed second. Any remaining rules in other agenda groups can then be executed. Therefore, the "report" and "calculation" groups must receive the focus to be executed in that (that -> reverse) order (add? due to the agenda stack), before other rules can be executed:
Set the focus for the order of agenda group execution
 {{Agenda agenda = ksession.getAgenda();
agenda.getAgendaGroup( "report" ).setFocus();
agenda.getAgendaGroup( "calculation" ).setFocus();
ksession.fireAllRules();"}}
{{}}
{{}}