The Harvesttide is a Standard event, but the MID set is missing from the list of legal sets
MID is the set that has most of the transform cards in it! There are event objectives that need that!
This isn't the first time MID has gone missing from a Standard coalition event:
https://forums.d3go.com/discussion/90092/sf2-no-mid-cards-available-fixed
Concurring with the above, this event is directly linked to this missing set of Innistrad Midnight Hunt that contains a lot of objective based cards for The Harvesttide coalition event. A big one that many players use for the flip to Day/Night objective that is missing is The Celestus card itself.
There's a lesson to be learned here. Objectives that are limited to certain sets or worse, to subsets of cards like Pirates, limit player agency more than they create challenge. It was inevitable that it would one day limit the event itself.
They swapped it out for The Kamigawa Run.https://forums.d3go.com/discussion/90082/mtgpq-sneak-peek-april-week-4-updated-04-26-24#latest