Found answer to this
It’s probably an assumption by touring plans at this point. Calendars are shuffled all the time until maybe 6 weeks before.
IIRC that date was the second postponement, I think they usually try to do them earlier in the year. I believe the original date was in January.
I’ve seen the first date posted somewhere on WDWMagic and it is in January. Not sure which park or even whether the park was mentioned.
I’ll see if I can dig it out. But when park times are loaded for January it will be pretty easy to spot.
The date in May in Touring Plans will just be as a result of last year’s postponed event.