Can you remember all of your characters' attributes when you are writing a story? Or do you sometimes forget some of their attributes and/or give them traits that do not agree with their established persona? I mean, are your characters consistent throughout the story/book, or do their characters undergo any unwanted, inadvertent changes?
I caught myself making minor changes to minor characters - with the major characters I didn't seem to have that problem. Making mistakes is normal - you just have to be thorough enough with your editing process to catch them.
All of the above Mans, it's part of writing. As part of the editing process you would pay much more attention to details such as character consistency. In the current version of my novel my main characters are all over the place, in some areas they are emotionally flat, in others they are strong, in yet others they are fragile and weak. I'll work on these in subsequent edits and get some consistency going but for now, I'm just writing.
if/when i do, i correct it in one of the many edits the ms undergoes before arriving at a final, polished draft...
I don't forget anything important about my characters. They are the reason I write. If I could forget anything important about them, I'd have no story. I don't describe my characters' appearances very much, so I don't care what color their eyes are. I rarely mention their backstories, too, so I don't care where they went to school or what their fathers did for a living. I'm mainly concerned with how they deal with the situations they find themselves in. That's my motivation to write their stories in the first place, so what's important about the characters is always front and center for me.
I don't really forget anything about my characters, either. It's not so much remembering things about them, like I'm memorizing some rote list, but more that I know them, so I just know how they would think about something. I don't have to think, Oh yeah, John is an extrovert. He would go talk to that woman. I wouldn't be writing about John approaching a woman he doesn't know and then go back and think, "oh wait - John is shy and an introvert. He wouldn't do that." I already know what he's like. I know his personality. I know whether he'd approach an unknown woman, and if he did, how confident he'd be. When I'm writing him, I'm in his head. Even if I have him do something he wouldn't ordinarily do, I know that he's doing something he wouldn't ordinarily do, and he acts accordingly.
With some of my minor characters I know I am a bit inconsistent at times, Probably because with them I found myself assigning characteristics to them instead of letting them develop. With my MC and other more important characters I let them develop on their own, they feel like real people to me and each has developed their own personality and I feel like I am doing pretty well at keeping them consistent. I hope with time I will get better at developing minor characters.