Binding issue with digitally synthesized block

Hello ,

I synthesized a digital block from it's .v code and imported the GDS into Virtuoso. I also imported the same .v file into Virtuoso to create schematic corresponding to the .v code

I am seeing imported GDS is showing unbound instances which are all from digital pdk lib.

What can be the issue and how can I resolve it ?

I am using IC618 

Also when I instantiating this digital block at the top level for routing the flight lines are not visible for connections at the top level. 

thanks