Although the configured loopback address is 172.22.2.1/24 but by default OSPF will advertise this route to loopback0 as 172.22.2.1/32 (most specific route to that loopback). In order to override this, we have to change the network type to point-to-point. After this OSPF will advertise the address to loopback as 172.22.2.0/24.