I have replaced a 1072 with a CRS317 for pure routing purposes bgp v4+v6
I route about 1000 ipv4 routes and 900 ipv6.
I have replaced the 1072 to the 317 to have more ports, hardware lacp, and hardware routing. no other services on it.
I have seen the following.
on the network, at 6 hop distance from the 317, I have a router 2004 with 7.5 working OK.
It has 3 redundant path through our network, then they reach the crs317, wich uplink is towards the border routers, from where it receive the default route.
If I shut down just one path on this router 2004 (he receives the default on the three links with bgp), it cannot reach the internet, the traceroute stops at the 317.
The 2004 receives correctly the default route, everything as expected, but the traceroute stops at the 317.
If on the 317 I disable then re-enable the l3-hw forwarding, it works immediately.
I can reproduce it if I shut down any of the redundant link on the 2004.
I have seen is on the 7.5 and on the 7.6rc3
Obviously I cannot stay with l3-hw disabled since the 317 is not enough to route 6+ Gbps.
The very same identical conf, worked perfectly on a 1072 with fastpath and 7.5