Is an oath sworn on the Qur'an considered void if the one swearing is in a state of ritual impurity (junub), and does this entail a sin that necessitates expiation?

Regarding sin: We hope that there is no sin upon you for touching the Qur’an while in a state of ritual impurity (janabah) and breaking your oath, as long as you were forgetful and had a misinterpretation.

Regarding expiation: Scholars have differed concerning one who performs the sworn-against act based on a misinterpretation: Is he excused, so no expiation is binding upon him, or is he not excused? And whoever imitates those who say expiation is binding, that is closer to caution.