Load balancing and failover, traffig going out of one interface only.

Hi guys, it is my first time trying to get some help online. I am not some advanced user with Mikrotik to say. Anyway, I have set up load balancing with two WAN connection and at first it seemed to work fine, while monitoring interfaces I see traffic is passing from both. But I noticed traffic going out of one interface will have bot PUB IP’s as source, of WAN1 and WAN2 connection. Same for other interface.

I was expecting all traffic marked for WAN1 would leave router out of WAN1 interface with source IP of WAN1 connection and vice versa. But somehow they mixed up. Is this normal behavior or definitely is something wrong with mangle rules?

Cheers.