I feel it's kinda unfair for the duke not to know that leo is a whole grownup woman inside...

I think with how leo is acting like a pervert and talking like an old lady, there's not much of a discrepancy.

But then again, the fact that leo was a transmigator doesn't seem to be an important premise. Like it just seems to be a convenient explanation why leo knows a lot of things or is quick to grasp what is happening coz of reading the story.

I disagree i feel like aside from the very beginning and in specific scenarios leo doesn't behave like a child at all, she's immature but in an adult way, not like a standard little kid. To me at least she's always felt like a teenager or young adult, not ever a little kid.

Leo definitely didn't act like a child lol. A child is like her children peers. The way I see it, Leo currently live much freely compared to her previous life. That's how an adult with freedom and healthy family act. There are times when it's shown how much she kept inside as much as she let out just like an adult. She also expressing and discussing things maturely.

Even so, she's currently in a child's body. I don't think there's nothing wrong with her behaving like a child. Previous life is a past. Current is what matters

usually when i read stories like this, my head canon is that even though they are adult in a child's body, the body is still a child. therefore, the organs are not well developed compared to an adult body, especially the brain. so although they act or think maturely, the child's brain will surely affect them in some ways, resulting in some mc being more emotional or immature at times.

like i said, this is just my head canon so that i dont get the "ick" when reading something with the similar plot, especially if the plot is really interesting. it's really just one of my ways to enjoy reading