Turns out the one spreading the rumors was Hashimoto, who did so at the behest of Sakayanagi. Shortly thereafter, Sakayanagi appears before Class C and she informs them she has evidence regarding the rumors about Ichinose.
You're not, Ichinose!
!لستِ كذلك يا إيتشينوسي
Von wegen erbärmlich!
No es verdad, Ichinose.
No es verdad, Ichinose.
Ce n’est pas vrai, Ichinose !
Non è così, Ichinose!
Pare com isso, Ichinose!
Ничего подобного, Итиносэ!