I've got two guesses for what happened.
Either she finds out about the girlfriend after the fact and completely shuts him out.
Or the girlfriend finds out about her and fucking attacks her.
Likely a combination of both.
Either way I get the impression that in the present he doesn't actually...
Remember Rokudou is trying to avoid a future where Ranna goes on a rampage. He's prioritizing trying to keep her from fighting over everything else.
Not to mention that he suffered a very deep and special trauma with this guy. For Rokudou this guy is worse then everyone else he's faced up until...
Shut up with the "block the group" malarkey. Often times other translation groups will skip chapters that were done like this when they reach them leaving gaps in the chapters and you won't be able to see why they're missing because you blocked the group that made it.