In recent chapter, his right hand has short nails while the left hand kept its long nails. The author truly persistent with such detail that the nail not just suddenly become short when it need to do its job ლ(´ڡ`ლ)
From my understanding, he have one hand short nails to have a way to show his human side and the other long for the ghost/demon side. It was mentioned in one of the chapters the brothers came from the underworld asking him why it has to be Nok and one of the twin said to the other if he noticed his hands because when he was a kid he did the impossible to grow the nails on his human hand/side.
im in ch5 rn, and all I could think about is how ML should trim his long, pointy ass nails