I say, and with God's success: The wiping over the two socks is invalidated by removing them or by removing one of them, so the wiping over the sock must be repeated; because the purity of the feet is indivisible, as they are a single duty. Therefore, it is not permissible to wash one of them and wipe the other. If one of them is invalidated, the other is also invalidated; necessarily due to the indivisibility. Refer to: Sharh Al-Wiqayah p.115, and Nihayat Al-Murad p.387, and God knows best.