[c-nsp] ME3600 BFD session to A9K breaks after upgrade to 15.3(3)S1a

[Jason Lixfeld]

Before an upgrade to 15.3(3)S1a, a BFD session between a 9K and an ME3600 worked just fine.  After the upgrade, BFD session wouldn't come up.  I looked at the release notes and couldn't see any notes about behaviour changes in BFD or any specific caveats.  BFD still works fine if the adjacent device is another ME3600 (only tested adjacent ME3600s that were *not* upgraded to 15.3(3)S1a).

I've got Cisco looking at it, but I'm just curious if anyone else has seen this change in behaviour.  Previously, this ME3600 was running 15.3(3)S and it worked just fine to this same 9K (which is running XR 4.3.1).

! A9K
!
router isis
 is-type level-2-only
 net 00.0720.1504.8009.0000.00
 nsf cisco
 log adjacency changes
 log pdu drops
 address-family ipv4 unicast
  metric-style transition
!
interface TenGigE0/0/0/6
  bfd minimum-interval 300
  bfd multiplier 3
  bfd fast-detect ipv4
  link-down fast-detect
  address-family ipv4 unicast
!

! ME3600
!
interface TenGigabitEthernet0/1
 no switchport
 dampening
 mtu 9216
 ip address 72.15.51.45 255.255.255.254
 ip router isis 21949
 logging event link-status
 carrier-delay msec 0
 mpls ip
 bfd interval 300 min_rx 300 multiplier 3
 isis bfd
!
router isis 21949
 net 00.0720.1505.0138.0000.00
 is-type level-2-only
 metric-style transition
 spf-interval 5 1 50
 prc-interval 5 1 50
 lsp-gen-interval 5 1 50
 bfd all-interfaces
!

Thanks in advance.