This behavior is expected due to a rate limiter of 250 that is set for ICMP.
To temporarily disable this limiter, enter the following Terminal command on the target Mac:
sudo sysctl -w net.inet.icmp.icmplim=0
This setting will persist until the next restart of the target Mac, then it will be reset to the default value of 250.
If you want to make this change permanent, open the sysctl.conf file located in /etc/ and add the following line: