WAN Link failover doesn't revert back SSL VPN connection (openvpn)

Hi, 

I've setup a Sophos XG with firmware 17.5.0 GA

It has 2 WAN interfaces setup as: WAN1_GW Active, WAN2_GW Backup (revert when primary restored)

Firewall is configured with SSLVPN Client to OpenVPN Server

I did the following tests: 

• check my WAN IP = A.A.A.A
• start SSH connection to public SSH host: OK
• VPN is active and working

Next I disconnect my primary WAN. This is what happens:

• check my WAN IP = B.B.B.B (OK)
• my ssh connection hangs, need to close and reestablish (OK)
• VPN times out, is automatically recreated after a few seconds through backup gateway (OK)

Then I reconnect my primary WAN interface. According to the settings it should drop all connections and start using my primary WAN again. This is what happens:

• Check my WAN IP = A.A.A.A (OK)
• my SSH connection hangs, need to close and reestablish (OK) 
• VPN keeps working through backup gateway (NOK!)

The only way to get my VPN get back over the primary WAN is to disconnect and reconnect the VPN manually. 

Why is the VPN connection not reverting back to the primary gateway? I want to use a 4G connection as backup, but I don't want to keep using it when the primary WAN is back online!

Is this a bug or I am doing something wrong?

Michiel.