You didn't answer me directly, but still it's my turn to apologise - I didn't catch that previous statement of yours about you disabling the wifi connection. 
In that case, your Pi-hole may still hold on to a previous DHCP lease for that .105 when your wifi was still active, which it may keep renewing as that client's associated MAC address would still show up on the eth0 link.
Please check:
grep -c raspberrypi /etc/pihole/dhcp.leases
grep -c 192.168.2.105 /etc/pihole/dhcp.leases
If that returns a count of 1 or more, please try:
sudo systemctl stop pihole-FTL.service
sudo nano /etc/pihole/dhcp.leases
Delete the line(s) containing the name and IP address.
sudo systemctl start pihole-FTL.service