I found this very weird too. The Crown Store Showcase for June now just says that "This item has been temporarily removed from the Crown Store and will return at a later date." But... how much later? What went wrong, how, what...? I was really looking forward to this one.
There was an issue for players that owned the High Isle CE (when it was sold as a Chapter) could purchase the Collector's Pack from the Crown Store. I'd guess that was the reason for it being removed for the time being. @ZOS_Kevin could probably confirm this.