any updates on this? I’ve been struggling with this issue for months!! I’ve posted numerous posts across here, reddit, and IRC that got me nowhere until I systematically disabled every rule in the firewall as a first attempt before re-configuring PCC from scratch and BOOM, it worked when Fast Track was disabled! despite what is said in the link provided by @mrz, the line immediately after the default Fast Track rule of accept has no effect and still breaks PCC unless Fast Track is disabled. if there’s a fix for this it would be welcome, but I’m glad to finally put this months long issue to rest!
EDIT: looks like the MikroTik gods have spoken http://forum.mikrotik.com/t/load-balance-pcc-pppoe-same-isp-gateway/100562/1