Is Router Pinging Local Hosts Normal?
It can be normal to see pings from a router. If you are using DHCP with conflict detection enabled it will verify if an address is in use (initiate a ping from a router to a specific IP address) before assigning it for use. If you are seeing this shortly after bringing a device on to the network – such as out of sleep mode – it’s pretty normal.
If you are curious search for “DHCP conflict detection” or check this article.