Networkscan already done, while IP 192.168.178.27 still waiting

Avast Free Antivirus / Premium Security
1

Running Windows 10 home V1607 build 14393.1066
Avast 17.4.2294 Final
Same problem in W10 Creators Upd V1703 build 15063.250 and W10 IP RS3 build 16184.1001nl

2

It has always been so for me when I use scan from network , waiting for my own device adresse .
Maybe a loopback routeur problem ?