Is it permissible to wipe over the khuff (leather socks) if impurity occurs before the foot is fully inside?

Primary text

It is not permissible for a person who has nullified his ablution (hadath) before his foot is completely covered by the khuff to wipe over the khuff when performing subsequent ablution. This ruling applies because the foot attained its established place (i.e., being inside the sock) while the person was in a state of impurity. This scenario is treated the same as if the wearing of the khuff began while the person was already impure.