[SOLVED] MSTP with port overrides

Hi, i m not sure if this is the expected behavior, or if i did something wrong.
But when a ping reach its destination (an ip on an vrrp interface) on the root bridge for a given vlan.
The root bridge forward the packet to other non-root MSTIs

the Topology : https://puu.sh/FIdHb/1a99ada88a.png
the ping sniffed on all the switches : https://puu.sh/FIdHQ/c639a91979.png

mixB is the region root for that vlan
path-cost between agrA <=> abrB, and mixA <=> mixB have been increased

The ping takes the right path, so for so good,
But i do not understand why mixB is forwarding it to mixA and agrA, as mixB is the root-bridge for that vlan and is owning the ping’s target ip.


EDIT:
Finally got the expected behavior, had to disable the “unknown-unicast-flood” on the interfaces inside the bridge on all the mix routers.