multi wan load balancing not load balancing after failover

[2fe4]

The issue I am experiencing is that load balancing sometimes fails to load balance after a WAN uplink is restored in a multi wan configuration.

Details:
Two WANs configured with both tier 1 in a gateway group named WAN_LB with trigger level set to member down. Default gateway in System/Routing/Gateways set to WAN_LB().

LAN firewall rule has the gateway set to WAN_LB. Load balancing confirmed to be working via curl to fetch WAN IP (I see it cycling between both WANs).

Testing: When WAN1 goes down, traffic is failed over to the WAN2 as expected and WAN1 shows offline in gateways. Once restored both gateways show online, but traffic is only being directed out over the WAN2. This does not happen 100% of the time, but is reproducible over several attempts. As far as I've seen, once it happens it stays in the broken state until some kind of intervention.

The "fix" is any one of: restart gateway monitoring, re-save gateway settings. Basically almost any config change.

Version: 2.6.0-RELEASE

Use sticky connections: UNCHECKED

Flush all states when a gateway goes down: UNCHECKED

Do not create rules when gateway is down: UNCHECKED

If anyone has a pointer to a setting I've missed or any help in debugging it would be appreciated.