On Junos OS Evolved platforms, when no acknowledgment is received from PFE (Packet Forwarding Engine) within timeout results in the rpd (Routing Process Daemon) crash. 
This issue happens when routes requesting acknowledgment do not receive acknowledgment leading to segment fault.

The rpd crash will be observed due to segment fault resulting in traffic impact when routes requesting acknowledgment are waiting for acknowledgment
from the forwarding plane, but before that, the acknowledgment timeout has happened.

To check the rpd core files, execute the CLI command:
user@device> show system core-dumps

This issue might be seen if the following conditions are met:
* On Junos OS Evolved platforms
* Routing Protocols configured
* Acknowledgement not received from PFE i.e. acknowledgment timeout

Restarting the rpd post crash the rpd remains stable
Need fix of the PR1785884