[j-nsp] Wierd problem with RE-based sampling on 12.3

[Tom Eichhorn]

Dear all,

I have a very curious problem with some box running
JunOS 12.3, DPC-based:

I have one interface towards some upstream provider and want to
generate cflow for in- and outbound direction and have the following
configuriation:

teichhorn at somerouter# show forwarding-options
sampling {
    input {
        rate 2048;
        run-length 0;
        max-packets-per-second 4096;
    }
    family inet {
        output {
            flow-active-timeout 60;
            flow-server a.a.a.a {
                port 9000;
                autonomous-system-type origin;
                source-address (ip lo0);
                version 5;
            }
        }
    }
}

teichhorn at somerouter# show interfaces xe-0/3/0
description "TRANSIT - XXX";
unit 0 {
    family inet {
        sampling {
            input;
            output;
        }
        address c.c.c.c;
    }
    family inet6 {
        address a:b:c:d::1/128;
    }
}

(It doesn't matter if I use family inet sampling or a firewall filter)

All the flows which are exported only contains the outbound packets,
but no inbound ones.

Has anyone seen that before or has a hint? I would like to open a case
the next days but like to hear your opinion before...

(And no, I can't simply put output sampling on the other interfaces,
since there is MPLS forwarding on them active...)

Thanks,
Tom