Thank you for your help Adam.
I do see multiple entry for same ip address. Please check screenshot below and you can see APIC-EM shows 172.16.64.90 and 172.16.68.91 are connected to switch53 and swtich54, but it’s wrong. They are actually connected to another switch. I couldn’t understand how it happened.
Also the topology generated by APIC-EM is totally wrong. Some switches are on different site, but the topology shows they are connected directly. How can I fix those issue?
Cheers,