Hey, I had the same bug and got the reply that the issue is known and is being investigated, no fix for now it seems.
If any devs are reading this, I'd still appreciate clarification on if this is a matter of new dialogue not triggering when it should, or just a visual bug where the speech bubble is there even though no new lines are supposed to be unlocked.
TBH, this bug has been ubiquitous since the beginning, has been especially rampant on Xoti, and despite having been "looked at" for more than a year, it's still popping exactly as much as the day of release.
In fact, I even checked if I didn't install the game with an old file (from GOG) because I am constantly pretty often such sort of glitches that were supposedly "looked at" or "fixed" for months and month.
I'm pretty tolerant of buggy release, but FFS we're one whole year and three DLC later, at patch 4.0, and it's not acceptable anymore.