Well, its due to ping spikes.
About xtm's questions, there is a ping limit in EC, it checks when you spawn not after it. I & many other admins kick players for high pings, if you see any player with these ping spikes, just do /report because admins play ingame also so they don't check the list all the time.
A message to karan & other ping spikers, I also face ping spikes rarely but I dont play or if I join server, I dont spawn & wait for it to get normal, so like a responsible player, you all must do it also, dont stand on free spot because if you are spawned, surely others will try to kill you.
Denied.