Pokemon Mystery Dungeon: Explorers of Time/Darkness Easter Egg - Luminous Reference

When you have defeated Darkrai, and Palkia shatters the Dimensional Hole, it goes into "spoken" text by your partner. He makes a point to tell you that, "We have returned to Luminous Cave since then, but we still couldn't evolve." In Pokemon Mystery Dungeon Red/Blue Rescue Team, Luminous Cave is where you go to evolve. In Time/Darkness, you evolve at Luminous SPRING. Therefore, your partner was referencing the original evolving spot.