On UI side after NSX Edge failover, HA status at gateway level is not updated immediately and it takes 5 to 10 minutes.
The failover status can be checked by following these steps:
1. Navigate to Networking Tier-0 Gateways or Tier-1 Gateways.
2. Click "Active Standby"
VMware NSX
VMware NSX-T Data Center
When the refresh button is pressed on the UI, the API that is executed retrieves the cached status of the NSX Edge, which may cause a delay in the state transition.