Charm is the stat that you have it at Max of 50 and it is like Energy. Social actions cost charm, when it is too low you can't do any social actions. It is supposed to recover a little when you rest, don't interact with NPCs. At 6 you can't do most interactions with other characters. When you intact with characters the interaction lowers the stat till you wait enough, rest, for it to recover. Defaulting to 6 is definitely a bug as it will drop from 50 to 6 with out you doing anything with the NPCs. You can be at 50 just go shower or sleep and it goes down.
19.00 didn't have the bug. 19.10 with the SLDR mod does. Not sure if it was the 19.10 patch or the SLDR mod that did it.
Wit sis I get no favor option to get stuff like Denise and mom. I know that with Denise if her stats weren't at certain at certain values you couldn't trigger the favors. Just can have sis skip class or go some place private.
With Sophie I've grinned to the point in past games that me and her have sex after she gives BJ and mom leaves. It looks like some sort of shower from what I can tell by the pics.
Are you talking about the cheated version, then disreagard the rest. Otherwise this is simply not true.
Because without cheats 6 is your natural charm with the first perk as social.
Your Natural Charm is 3 + Your natural Social + power bonus. Your natural Social is maximum 6 with +2 from the perk and 3x training and the bonus from Powers is maximum 2 or 3 in the current game, so without cheating you can have a maximum of 8 or 9 Charm, if you trained everything that influences Charm. This is even listed in the tooltip, when you hover over the charm stat.
Also pretty much all social actions cost either 1, 2 or 3 charm. Having 6 Charm doesn't lock you out of anything, it just limits the maximum amount of actions you can take.
Not to hate, just to clarify, if someone else wonders, why he "only" has 4, 5 or 6 Charm at gamestart.