The Fortinet FGSP (FortiGate Session Life Support Protocol) cluster allows session synchronization between two FortiGate devices to provide seamless failover. However, ICMP (ping) is a connectionless protocol, and by default, FortiGate does not synchronize connectionless sessions unless explicitly enabled.
In the exhibit:
# The command get system session list | grep icmp on FortiGate_B returns no output, meaning that ICMP sessions are not being synchronized from FortiGate_A.
# If session-pickup-connectionless is disabled, FortiGate_B will not receive ICMP sessions, causing packet loss during failover.

FortiGate_A and FortiGate_B are in the same autonomous system (AS), and FortiGate_A does not currently have route 172.16.1.248/30 in its routing table. However, FortiGate_B has this route as a connected route.
To dynamically advertise only 172.16.1.248/30 from FortiGate_B to FortiGate_A, the administrator must configure a BGP route map out on FortiGate_B that specifically permits only this prefix.
A BGP route map out on FortiGate_B controls which routes FortiGate_B advertises to FortiGate_A. If no filtering is applied, FortiGate_B might advertise all BGP-learned and connected routes, which is not what the administrator wants. The route map should include a prefix-list that explicitly allows only 172.16.1.248/30 and denies everything else.