FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
If following logs in the FortiGate crash log are noticed:
324: 2021-02-25 08:44:03 the killed daemon is /bin/pyfcgid: status=0x0
This article will explain this.

The pyfcgid refers to a python script which is usually generated when the GUI times out.
324: 2021-02-25 08:44:03 the killed daemon is /bin/pyfcgid: status=0x0
Refer to the 'cleaning' of this script, which is killed/restarted by the FortiGate.
/bin/pyfcgid: status=0x0 <-----
status=0x0 means that this process will be terminated and deleted so that kernel can give space for other processes in terms of resource allocation.

In other works, status=0x0 is normal process shutdown due to job done without abnormality.

Thus, if these messages are visible in the crashlog, there is nothing to worry about this message.

Internal Notes
Forticare ticket# 4736001, 2445248.