Endless Eight was organized to be produced as 6 episodes.
Kadokawa's back sponsor got furious and by the time it was too late, the producer had been fired.
There was huge confusion over whether they were going to skip the produced 4th and 5th episodes and skip to airing the 6th.
By the way, the 6 ep organization was Kadokawa's instructions.
The fired producer was a scape goat to appease the angry back sponsors.
Kadokawa's ultimate goal was to blow smoke over the fans by having 12 episodes that would consist of E8, Sigh, and a new Mikuru's adventure.
And the disappearance images they had pulled from would remain exactly that... (Unsure)
Currently Kadokawa does not feel like animating Disappearance
The purpose of this new production is simple to pull money from the fans (Extreme paraphrase)
Looks like Kyoani wasn't the troll master!
Kadokawa is the Ultra Troll master!