In my layout in magic, I placed one instance of pfet with finger equal to 2 to represent two pfets with source connected together (they has two seperate poly). The width for there two pfet are both 1um (shown in pic below). Same for nmos, I only placed one nfet in layout with finger equal to 2 to represent two nfets with source connected together. There are no property errors for nmos. I think pfet width in schematic and layout are both 1um. I am confused about this property error.

Can you post your spice files? The one extracted from the layout and the one created from the schematic.

Hi Mitch, thank you for replies! The mux_test.spice is extracted from the layout. The mux2-1.spice is from schematic.