Blizzard has released Hotfix 11 for Patch 1.0.2, fixing issues related to players having access to World Tier 3 & 4 without completing the required Capstone Dungeons.
Cathedral of Light Capstone Dungeon Guide Fallen Temple Capstone Dungeon Guide
HOTFIX 11 – JUNE 15, 2023 – 1.0.2
Bug Fixes
Resolved an issue where players in World Tier 3 and World Tier 4 could invite others to their party that were not eligible for those higher tiers.