is bleach: thousand-year blood war (bleach: sennen kessen-hen) episode 18 filler?

Within 12th Division Captain Mayuri Kurotsuchi's hidden laboratory, one of the technicians monitoring the replaced Seireitei brings up a topographical map of the city produced by the Wandenreich and announces that the Gotei 13 has roughly 42% of its forces currently alive, but its active military strength is less than 30%, prompting 12th Division 3rd Seat Akon to curse at the Wandenreich trampling them in such a short amount of time as Kisuke Urahara notes they have crushed the Gotei 13's chain of command.