I assume you have the "loaded/weighted die" setting on? (It's the default setting.) Larian added this weighted dice system to "fix" the streakiness of their rng, and in a recent hotfix they made it so only low-valued streaks were eliminated from their rng (allowing players to still get "hot streaks"). It is possible that their recent hotfix has broken this mechanic, but again this can't be determined with only 9 rolls. It is equally likely for you to only roll values above 15, but in this case you probably wouldn't feel strongly enough to make a forum post.
If you don't have the "loaded die" setting on, then yes the fact that Larian's rng produces multiple consecutive low-numbered values in a row is a known issue. It does the same for high-valued rolls. It baffles me how Larian ended up choosing such an obviously poor random number generator...
I would be very interested in determining if Larian's recent hotfix to the loaded dice system is actually broken. If you're (plus a combination of other people like @EvilVik) willing to record even 100 rolls, we could at least test whether the average roll is close to the expected average of 10.5
I played with loaded/unloaded dice, not sure which way it is now, will have to check. But since it is a known issue, I apologize for stressing it again, I'm new to the community. I did the search on dice before posting but didn't find anything specific.
However, the main and possibly the only reason why I brought it up in the first place, is the fact that different characters from different playthroughs, faced the same challenges in the same situations, including some dialogues. That's where the feeling about the game "not wanting" you to succeed in certain areas is coming from.
Sorry, I cannot be more specific at this time, it's late and I am melting, but frequent deja vus in game inevitably inspire a suspicion. Anyway, you and others have convinced me that this is not intended by design but rather imperfection of it. Well, almost convinced me, it doesn't explain different character-same outcome thing, but I can find content in fact that this is something that is being discussed and probably worked on.
Thank you everyone for your explanations.