Verify that your symbol pin numbers perfectly match the node order declared in the .subckt line of your model file. A standard CD4051 subcircuit line typically follows this convention:
Because the CD4051 is essentially a set of eight voltage-controlled switches and a 3-to-8 decoder, many SPICE veterans don't use a link at all. They use a generic cd4051 spice model link
often provide more realistic transmission gate (TG) behavior compared to basic "box" models. Supply Voltage: Verify that your symbol pin numbers perfectly match