Symptom:
A path received from a neighbor may be marked "stale" permanently, or some paths received from a neighbor may get deleted.

Conditions:
All the following conditions must be satisfied.

1. Graceful restart or long-lived graceful-restart is configured for the neighbor,
2. The neighbor undergoes a session reset caused by the peer device closing the socket. 
3. Either of the following happens in the middle of a period during which BGP is processing all its paths for marking them as stale or deleting previously marked stale paths:
 3a. The neighbor session goes down.
 3b. The neighbor session comes back up and the the neighbor advertises one or more its routes.