BGP installing a BGP-learned route into the routing table
A BGP-learned route will be installed in the local routing table only if the local router has a valid path to the next-hop IP. For example, if R3 learns about 184.108.40.206/32 from R1 which has an IP address of 192.168.12.1, the R3's BGP table will look something like this:
R3#show ip bgp Network Next Hop Metric LocPrf Weight Path * i 220.127.116.11/32 192.168.12.1 0 100 0 1 i
In order for this network to be installed in the routing table, a valid route to the next-hop IP of 192.168.12.1 must exist in the local routing table. Note that even a default route in the local routing table would be considered a valid route to the next-hop IP for BGP to operate.
Remember, BGP peers may be several hops away, and such a network prefix may be learned via a BGP Route Reflector, so it may be the case that 192.168.12.1 is indeed not in the routing table.