Good catch — and those aren't six different quests. It's the same event quest that Nexon re-ran five times between 2002 and 2010, each re-run given a fresh ID and its own start and end dates, so only one of them was ever live at a time in the real game. (The odd spelling on one of them, "Nostaligic", is a typo in Nexon's original data, not ours.)

We deliberately switched off the expiry dates so that no quest is permanently locked out of this server. The side effect is exactly what you're seeing: every re-run of a repeated event now shows up in the NPC's list at once. The fix is to collapse rows that ask for the exact same thing, so Teo shows one entry per actual piece of work instead of one per historical re-run.

Fix shipped — this is now on develop and will be in the next build.

The diagnosis is in the comment above; this is just to confirm the change is written, type-checked, built and pushed rather than only planned. Please re-test when the next build goes up and reopen if it is still wrong.