We have these rules in mangle:
28 ;;;
chain=prerouting action=mark-connection new-connection-mark=one passthrough=yes connection-state=new in-interface=ether3 (MaruCom Network) nth=2,1
29 ;;;
chain=prerouting action=add-src-to-address-list address-list=one address-list-timeout=4h in-interface=ether3 (MaruCom Network) connection-mark=one
30 ;;;
chain=prerouting action=mark-routing new-routing-mark=one passthrough=no in-interface=ether3 (MaruCom Network) connection-mark=one
31 ;;;
chain=prerouting action=mark-connection new-connection-mark=two passthrough=yes connection-state=new in-interface=ether3 (MaruCom Network)
32 ;;;
chain=prerouting action=add-src-to-address-list address-list=two address-list-timeout=4h in-interface=ether3 (MaruCom Network) connection-mark=two
33 ;;;
chain=prerouting action=mark-routing new-routing-mark=two passthrough=no in-interface=ether3 (MaruCom Network) connection-mark=two
They worked for more then a year in several ros versions but after last upgrade to 3.11 we are continiously seeing double scr-address list numbers been produced. As a result router becomes confused and traffic dies out on my clients. To work around the problem we have to erase duplicates manually every hour… 
We have been trouble shooting with the guy that sort of invented this loadbalancing routing in ros but we don’t seem to get our finger on it…
Any suggestions from this forum is appreciated…