This isn't "random", it's dying because the uplink IRCd is disconnecting it for not responding to pings. Check to see if earlier in the logs it shows receiving a PING from irc.CriticalSecurity.net. (I'm not sure what the token for that is, but look for that too, check Unreal's docs to find out what the PING token is in Unreal.) Also, make sure that Anope is u:lined, and also make sure it is using a connection class that actually pings the server enough to prevent a ping timeout.