If you are bombarding addresses with frequent ping packets they gonna throw those away due to a more strict ddos protection, not because of actual packet loss.
Set yout ping interval to 10 seconds and there will be no ignored packets.
If you ping your own router fast enough you gonna see packet losses there too.
Very good points that is in effect a DDOS and increasing the interval will help to prevent the server from assuming you are DDOS'ing, also depends which ports you use for the pings, given the amount of data and packets sent during gameplay on the servers.
