Just completed tidal Basin with my group that we’re already world tier 5 and now I’m stuck in world tier 4 no progressing to world tier 5. Utterly useless.
Were you GS 425 before you started Tidal Basin?
If you complete it while being under the GS requirements, you will not be bumped up to World Tier 5.
If you go back to single player game, is Tidal Basin available for you to play on the map?