This issue is essentially due to a the allocation of the same IP addresses to both the Host WiFi adapter (by the wifi router's DHCP server) and the Guest interface (by the VirtualBox DHCP server under Nat networking).
This issue is essentially due to a the allocation of the same IP addresses to both the Host WiFi adapter (by the wifi router's DHCP server) and the Guest interface (by the VirtualBox DHCP server under Nat networking).