Symptom
lslib database shows stale ISIS entries
ISIS is not updating lslib database
Conditions
Problem happens when ISIS is configured with "distribute link-state" which implicitly applies to both isis levels, and user disables only one level by configuring "no distribute link-state level-1" (or level-2).
ISIS and bgpls library get into inconsistent state, isis entries stay in bgpls forever, and isis will not be able to reconnect to it.
Workaround
Remove the bgpls distribution from isis configuration for both level first by doing "no distribute link-state"
in the router isis submode, and then enable bgpls for the desired level only.
Further Problem Description
Once the router gets to the problematic state, the only recovery is to reload the router.
