SD-WAN required to take more than 20 seconds to failover from primary WAN port to secondary WAN port

[Cheah]

I have set up a network as the image below. The network has two sides, one is HQ and another is Branch, and they are communicating by using Side-to-Side VPN Tunnel. The firewalls' policy allows any traffic and SD-WAN policy is Source: Any, Destination: Any, Service & Applications: Any, Behavior: Overlay-VPN with All Relevant WAN Links. 

After setup this network and I unplug the WAN port 1 at HQ-Router-1 it will failover to HQ-Router-2 WAN port 1 with just 0 to 2 seconds, but once I unplug again the current using WAN port which is HQ-Rotuer-2 WAN port 1, it will have 20 to 30 seconds downtimes to failover. It this normal? Are there any latent factor that will cause this issue happen? Because what I have read from the Quantum SD-WAN documentation it supposes should have "sub-second failover"

[Chris_Atkinson]

Can you confirm that the gateways are centrally managed and using firmware R81.10.05 Build 996001301 or something else?

Note SD-WAN for Quantum Spark is currently in EA.

[Cheah]

Hi, the firewalls at HQ network and Branch network are using R81.10 Security Gateway with SD-WAN Support and managed by using Smart-1 Cloud. Other than that, the "Internet-Router" is using R81.20 with standalone mode. 

[Cheah]

Hi, the firewalls at HQ Network and Branch Network are using R81.10 Security Gateway with SD-WAN Support and they are managed by Smart-1 Cloud. Other than that, the "Internet-Router" is using R81.20 with standalone mode.

[the_rock]

I would involve TAC in this.