Kaynide: I checked, you were right . its been run twice:

April 16, 2019 - May 27, 2019

and

September 13, 2021 - October 18, 2021

IF that timeline is right, even on average, we could guess two years between events, so MAYBE Sept - Oct 2023. Maybe.

BUT

We have The Rising end August, then Moogle Tomestones Event running to launch 6.5. Call this a guesstimate only, my money says it gets run after patch 6.5 launch.

Until we get an update ( maybe at the next Fanfest???) all we can do is wait.