Its just a subjective matter. I don't think it kills the flow of the story. And now that I think about it, she's not a total fluke. But the misunderstandings does destroys these character's credibility. And that's probably the only fluke she has. Another thing is that I can't stand why she need to have a good morality in such a setting. The requirement for a validated MC is a waste of settings.
Think of it this way. Why the Original Fml wanted to feel love as a family in the first place when all she knows is killing, scheming, and competing for a throne only in the end no one was beside her other than herself?
The transmigrator/reincarnated person wanted to achieve that goal for the original fml because she can relate. In order to reach that said goal. She has to blend in a while at the same time retaining her "Good morality". Otherwise, we got a case of another Roxanna wannabe situation (Fkup family, and in order to survive you have to become one at the same time lose some parts of humanity and morality just to survive in a fkup situation)
The misunderstanding part does kill the story in some way ngl.