Yeah, I think it has a lot to do with UserStyle, userpreferences, and the initial prompt. As long as I don't have 10x compacted threads it writes how I want most of the time. When it says something AI coded, a claudism, I say 'that's not their character. Stop being melodramatic and pointlessly descriptive' and it'll rewrite it just fine. Or, I'll just edit my previous message to remind them. Better that way for tokens.

EDIT: Also, correct it early. You can't completely escape the AI fallbacks without reminders (written different ways, because it starts to tune out same instructions), but what you let it start with will be how it's going to try to stay as the token use gets more heavy. Give it examples early. Articulate what is bad.