Have a look in the padsxxx.cfg file which you uses for creating netlist.
Here you find some rows
CHKBRD _SGL_PIN_NET WRN 2 | Single pin net
| 0 = Pass single pin nets to netlist
| 1 = Filter all single pin nets from netlist
| 2 = Filter single pin nets with the NET NC attribute from netlist
So, you can decide, what to do.
Klaus, thank you for your help, it works OK.