Okay, it's odd, but this is what I see.... I've configured a single loopback, as you have, and configured two ospf processes, each one with a network statement "covering" the loopback.
7206F#sho ip ospf 20 int
7206F#sho ip ospf 10 int
Loopback1 is up, line protocol is up
Internet Address 10.1.1.1/24, Area 100
Process ID 10, Router ID 144.1.1.1, Network Type POINT_TO_POINT, Cost: 1
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 0
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
So, as you say, the interface only shows up in one router. But, when I look at the database, I see:
7206F#sho ip ospf data router
OSPF Router with ID (10.1.1.1) (Process ID 20)
Router Link States (Area 200)
LS age: 186
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 10.1.1.1
Advertising Router: 10.1.1.1
LS Seq Number: 80000001
Checksum: 0x8A9E
Length: 24
Number of Links: 0
OSPF Router with ID (144.1.1.1) (Process ID 10)
Router Link States (Area 100)
LS age: 198
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 144.1.1.1
Advertising Router: 144.1.1.1
LS Seq Number: 80000001
Checksum: 0xAF4F
Length: 36
Number of Links: 1
Link connected to: a Stub Network
(Link ID) Network/subnet number: 10.1.1.0
(Link Data) Network Mask: 255.255.255.0
Number of TOS metrics: 0
TOS 0 Metrics: 1
Note that one shows a stub connection to 10.1.1.0/24, and the other one is using 10.1.1..1 as it's router id, with a length of 24. So, out of curiousity, I checked with a pair of connected routers, and found that only one of the two processes is advertising the loopback. Next I tried it with a normal interface, and found that it does the same thing here, so.... The only way to do this is to redistribute from one process into another.
Russ.W
