There is a bug with FRR 9.1.x.+, 10.2.+ that does not redistribute routes from Table X into OSPF.
Simple diagram
{F13921815}
To reproduce, add kernel routes in a table and redistribute this table into OSPF
VyOS `left` configuration (FRR 7.5.1):
```
set interfaces ethernet eth0 address '192.0.2.1/30'
set protocols ospf area 0.0.0.0 network '192.0.2.0/30'
set protocols ospf parameters router-id '192.0.2.1'
set protocols ospf redistribute kernel metric-type '2'
sudo ip route add blackhole 100.64.1.0/24 table 10
sudo ip route add blackhole 100.64.2.0/24 table 10
sudo ip route add blackhole 100.64.3.0/24 table 10
```
VyIS `right` configuration (FRR 9.1.2):
```
set interfaces ethernet eth0 address '192.0.2.2/30'
set protocols ospf area 0.0.0.0 network '192.0.2.0/30'
set protocols ospf parameters router-id '192.0.2.2'
set protocols ospf redistribute kernel metric-type '2'
sudo ip route add blackhole 10.5.1.0/24 table 10
sudo ip route add blackhole 10.5.2.0/24 table 10
sudo ip route add blackhole 10.5.3.0/24 table 10
```
Check the database on the router `left` expected kernel routes `100.64.x.0/24` in the database
```
vyos@left:~$ show ip ospf database
OSPF Router with ID (192.0.2.1)
Router Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# CkSum Link count
192.0.2.1 192.0.2.1 703 0x80000008 0x75bc 1
192.0.2.2 192.0.2.2 694 0x80000009 0xce68 1
Net Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# CkSum
192.0.2.1 192.0.2.1 703 0x80000001 0x8ac2
AS External Link States
Link ID ADV Router Age Seq# CkSum Route
100.64.1.0 192.0.2.1 798 0x80000002 0xa7ac E2 100.64.1.0/24 [0x0]
100.64.2.0 192.0.2.1 792 0x80000002 0x9cb6 E2 100.64.2.0/24 [0x0]
100.64.3.0 192.0.2.1 789 0x80000002 0x91c0 E2 100.64.3.0/24 [0x0]
vyos@left:~$
```
And we see those routes on the router `right` all works fine:
```
vyos@right:~$ show ip route ospf | grep 100.64
O>* 100.64.1.0/24 [110/20] via 192.0.2.1, eth0, weight 1, 00:13:14
O>* 100.64.2.0/24 [110/20] via 192.0.2.1, eth0, weight 1, 00:13:14
O>* 100.64.3.0/24 [110/20] via 192.0.2.1, eth0, weight 1, 00:13:14
vyos@right:~$
```
Check the database on the router `right` expected kernel routes `10.5.x.0/24` **NOT IN THE DATABASE**
```
vyos@right:~$ show ip route table 10
Codes: K - kernel route, C - connected, S - static, R - RIP,
VRF default table 10:
K>* 10.5.1.0/24 [0/0] unreachable (blackhole), 00:06:22
K>* 10.5.2.0/24 [0/0] unreachable (blackhole), 00:06:19
K>* 10.5.3.0/24 [0/0] unreachable (blackhole), 00:06:17
K>* 10.5.4.0/24 [0/0] unreachable (blackhole), 00:17:02
vyos@right:~$
vyos@right:~$
vyos@right:~$ show ip ospf database
OSPF Router with ID (192.0.2.2)
Router Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# CkSum Link count
192.0.2.1 192.0.2.1 951 0x80000008 0x75bc 1
192.0.2.2 192.0.2.2 941 0x80000009 0xce68 1
Net Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# CkSum
192.0.2.1 192.0.2.1 952 0x80000001 0x8ac2
AS External Link States
Link ID ADV Router Age Seq# CkSum Route
100.64.1.0 192.0.2.1 1046 0x80000002 0xa7ac E2 100.64.1.0/24 [0x0]
100.64.2.0 192.0.2.1 1040 0x80000002 0x9cb6 E2 100.64.2.0/24 [0x0]
100.64.3.0 192.0.2.1 1038 0x80000002 0x91c0 E2 100.64.3.0/24 [0x0]
vyos@right:~$
```
Of course, we don't see such routes on the router `left` due to this bug
```
vyos@left:~$ show ip route ospf
Codes: K - kernel route, C - connected, S - static, R - RIP,
O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
O 192.0.2.0/30 [110/10] is directly connected, eth0, weight 1, 00:19:17
vyos@left:~$
```