Wired Intelligent Edge

Hi, we have a client which has two 5710 switches  IRF stack. We can  not understand why IRF stopped forwarding traffic for ~2 min when  IRF stack active member was shutdown and after few minutes was turned back to power.

Standby member  took active member role, when active member went down and, but problem occurs when old active member tries to come back. Do we have active-active situation and we need to set up MAD BFD ir MAD LACP or MAD ARP? Or this is not the case?

MAC persistent always is turned on.

Deploying a Multi Active Detection (MAD) mechanism on a IRF is always a good practice.

Could you share your IRF's sanitized configuration?

Done that, did not help, used BFD MAD over direct VLAN

A good reason to share your sanitized IRF configuration. Could you share it?

Hi here is all configuration,
system-working-mode standard

#
irf mac-address persistent always
irf auto-update enable
undo irf link-delay
irf member 1 priority 32
irf member 2 priority 1

interface Ten-GigabitEthernet1/0/2
port link-mode bridge
port access vlan 4000
undo stp enable

interface Ten-GigabitEthernet2/0/2
port link-mode bridge
port access vlan 4000
undo stp enable

interface Vlan-interface4000
mad bfd enable
mad ip address 1.1.1.1 255.255.255.252 member 1
mad ip address 1.1.1.2 255.255.255.252 member 2

irf-port global load-sharing mode destination-ip source-ip

Problem was with Fortigate firewall. We had  to increase Fortigate LACP timer value.