UPDATE: The title's artist says the prequel has been delayed to October 2022, but Bleeding Cool's Rich Johnston is pretty insistent that this prequel has indeed been cancelled.
Original story follows:
Despite being advertised in today's new DC Comics, The Flash: The Fastest Man Alive three-part limited series has reportedly been cancelled by the publisher. This comes hot on the heels of the news that Warner Bros. has put all upcoming projects starring Ezra Miller on hold after the actor was arrested in Hawaii and later found himself the subject of a pretty serious restraining order.
Meant to serve as a prequel to The Flash movie, the main focus was going to be Ben Affleck's Batman training Barry Allen, with Girder, Tar Pit, and Top all set to factor into the story.
Now, you might be thinking this has something to do with The Flash recently shifting release dates from November 4, 2022 to June 23, 2023, but Bleeding Cool seems pretty confident that the series has been cancelled, and if it's already been printed (which is likely when it was supposed to hit comic book stores in two weeks), then chances are at least the first issue will have to be pulped.
Further suggesting this was a rash, last-minute decision is the fact that there was plenty of time to alter the advertising seen in today's comics after The Flash's release date was changed. Comic book retailers haven't even been informed of the cancellation, so this has to be related to Miller.
Considering the movie has finished shooting, it's hard to imagine the actor being somehow replaced at this point. However, it's not outside the realm of possibility that the ending of The Flash could be reshot so that Miller's Barry Allen is replaced with another version of the Scarlet Speedster (similar to how Affleck is being swapped out with Michael Keaton in the new DC Extended Universe).
Keep checking back here for updates on this one.