It's possible she caught that one time that Chika livestreamed giving him a blowjob, but I don't know if she ever mentioned that before.
She's about to see it very soon anyway. Who knew that being a scumbag to Niki would land Akira in being a homie with masturbation benefits with Rin.
I also wonder what Rin is going to talk about with Otoha during this update if the nude thing never happened. Cause boy, that's going to be a conversation. I wonder if Otoha will come clean in that scenario too, sort of "yeah dude, I'm a piece of shit, I even
"cheated" on you - you deserve so much more" kind of deal.