Policy based routing+static routing - unexpected behaviour

Hi there!

For some kind of traffic i need to pass it through a special device - gray box on a scheme.  For this purpose i added a Policy-Based-Rule which has an ingress interface Eth-trunk1.3 and egress interface Eth-Trunk1.4 , And it does work .  It forwards traffic towards the 172.31.2.2 and then to the Gray box

When i run PacketCapture on interface Eth-Trunk1.5 . I can capture all traffix soursed the group 1C-server and destined the group 1C-list.  The next thing i expected from Huawei USG is to pass this packets to static routing process and following the line ip route static 10.77.77.0 255.255.255.0 eth-trunk1.6 172.31.6.17   put this packets to Eth-Trunk1.6.  But it doesnt do this. Instead , this Thaffic again comes into interface eth-trunk1.4 forming a routing loop.

I tried to find a mistake  with Packet Tracing in diagnostic menu - it showed an absoluttely  correct way of the traffic  

(exported file shows traffic with the source 10.0.0.15 and the destination 10.77.77.58 coming out of the interface eth-trunk1.5)

flow:1

    packet:1

        FORWARD

            Layer 3 dispatch--------PASS: New packet arrived. 2618454562  interface:Eth-Trunk1.5 zone:dmz VRF:public -> public TCP  flag:SYN  10.0.0.15:22222 -> 10.77.77.58:445 pkt-id:160 

            Hook station process--------The process before the session table matching is passed

            Server map--------Server map: Session info, code:0x0, vsys ID:0, protocol:0x6

            User-manage ipv4 pre-fib identity--------UserId[0xffffffff]

            fib info--------Search fib info process done

            routing table--------Routing table process pass

            Interface access control process---Service manage of ipv4 packet process:next-hop=172.31.6.17, value=136

            User-manage ipv4 post-fib identity--------User management authentication pass (portal authentication)

            Layer 3 process--------packet filter recv packet

            Layer 3 process--------Layer 3 process pass: packet filter process done, rule name:rt-traffic

            Flow create--------Create session process

            Layer 3 process--------PASS: Layer 3 Flow process done

But in real life situation this traffic newer come to Eth-trunk1.6

My first suggestion was that PBR can not destinguish traffic between subinterfaces belonging to one physical interface. For this task i changed ingress interface to another one Eth-trunk1.19 and PBR stops forwarding this traffic. As i expected traffic was handled by the routing process and was  forwarded to the Eth-trunk1.6

Any suggestions? What could be done to resolve this problem?  

my version is: 

Huawei Versatile Routing Platform Software

VRP (R) Software, Version 5.170 (Eudemon200E-G V600R007C00SPC200)