If the type of the next hop is unicast, and when the next hop changes, it might trigger the PFE crash and impact traffic. A core file might be created and there will be temporary traffic interruption. 

Below messages might be seen in FPC messages or JUNOS messages log:

%PFE-3: fpc0 JPRDS_NH:jprds_nh_alloc(),990: JNH[0] failed to grab new region for NH 
%PFE-3: fpc0 JPRDS_NH:jprds_nh_seq_ocm_install_internal(),1681: Failed to OC install handle of Final(2)

On PTX Series routers and the QFX10000 line of switches, unicast next hop memory is not freed after unicast next hop changes. Once memory is consumed, the Packet Forwarding Engine might crash.

WORKAROUND

Configure link that receive NH under aggregate family.
Put link under an AE bundle with a single member.
In case of PFE crash, a reboot is necessary. You can reboot the chassis or connect via management port and request pfe reboot.

RESOLVED IN

The memory consumption increases due to memory leak

The Packet Forwarding Engine might crash due to NH memory exhaustion with unicast next hop changes.