New theory: Akane and co were at the site of the EM Nuke, and Akane had a mental breakdown/spent the week helping civilians whose lives were ruined by our actions.
New new theory: Akane decided to take matters into her own hands and has allied with Akatsuki to open the rift.
New new new theory: as I do not recall if Akane knew about the rift, she's decided to go no contact nukenin and become a wandering unseen ninja peoplehelpering person. Her students are focused on finding and convincing her to go back before it's blatantly obvious she is now a traitor.
New old theory: those self-immolation jutsu backdoors activated and now her and her students are ash in the wind.
New new new new theory: as Asuma needs a full retinue of ANBU for his trip, Akane has to go with them to be kept under observation. They told Hazou, who told Gaku to remind him, and then Hazou escaped his duties as clan lead before Gaku could do so.
Nnnnn theory: she is now apprenticed to Tsunade by happenstance
Nnnnnn theory: she has been contacted by the Kyubey. She wished to not feel the grief. She is now an amnesiac magical girl
Nnnnnnn theory: in becoming a female tragic figure with OP powers, she has been inserted into Worm and is currently being forced to use her elemental mastery against the nine. Pre-GM Taylor is in MfD having fun controlling 12 meter tall chakra centipedes.