Symptom
The import BGP route target that should allow leaf switches to import L3Out routes from another site is missing. As a result, the leaf switches with the missing route targets will not be able to learn routes from the remote site L3Out.
Conditions
To reproduce this issue, 3 Cisco ACI Multi-Site sites are required.
1. Configure 2 sites in MSO (don't add the 3rd, yet).
2. Add the two sites to a tenant.
3. Add the two sites to a schema. The schema should include a VRF table, an L3Out, an EPG, and a contract between the EPG and the L3Out.
4. Deploy the schema.
At this point, running "show bgp process vrf x" should show that leaf switches are importing the BGP route target from the other site.
5. Add the 3rd site into MSO and configure the infra.
6. Add the tenant to the 3rd site.
7. Deploy the schema to the 3rd site.
At this point it is observed that the original sites don't get the route target import that would allow them to import bgp routes from the 3rd site.
Workaround
Undeploy the schema from the site(s) where the route target isn't getting pushed. Redeploying the schema will then cause the route targets to get pushed.
