Game concept
Settlement Issue Tier
From the game's encyclopedia
Every Settlement Issue has a Settlement Issue Tier, which reflects the overall rewards of an Issue when successfully solved. Solving an Issue with with a higher tier will typical in more rewards in addition to the County Control.
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Settlement Issue Tier is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Every Settlement Issue has a Settlement Issue Tier, which reflects the overall rewards of an Issue when successfully solved." Patch 1.20.1.2, from game/common/game_concepts/mpo_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/mpo_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.