vRouter stopped forwarding user plane traffic with no reason

[Jacopo Pianigiani]

During testing of a simple service chain (MX VRF-Virtual NEtwork with same RT, Service instance = vSRX L3 firewall , Virtual Network RIGHT with same RT as VRF_OUT on MX, then inet.0), vRouter stopped forwarding USER PLANE TRAFFIC (while BGP routes where correctly advertised to MX).
All labels and GRE tunnels were u[p and running, the VM was up and running but performing TCPdump on the vRouter vif, i saw that the traffic was NOT forwarded between the vROUTER and the VM Service instance.
The only way to solve the issue was restarting vRouter completely

a) One of the VRouters Compute nodes (Compute 85) stopped forwarding traffic on user plane.
b) Routes were advertised correctly to the MX and we could see all routes coorectly in each ingress and egress VRF
c) Using flow –l we were able to see the flows in vRouter with the correct action (forward) , but
a. Traffic did not get forwarded through the service instance of each service chain
We did some troubleshooting without any success. We then did a reboot of the vRouter itself and it restarted forwarding traffic. The root cause of the failure is still not understood.

[Ashish Ranjan (aranjan-n)]

Given the description we do not know on which release this was observed. If this is reproducible in 1.1 onwards hari can take a look.