I take it back… I also have problems with https. Looks like there is work needed to be done to overcome this problem in “Load Balancing and Failover” mode.
One good approach is to hash the url and send the packets from the same interface for the same addresses. Or to bind the destination IP address with a specific interface.
Temporarily I created 2 static rules, one for 0.0.0.0/126.96.36.199 and one for 188.8.131.52/184.108.40.206 . That should load balance somehow the packets correctly till we find out a solution.