This behaviour is totally normal, you should see the exact same sort of lines on your other server. The masterserver will drop any server from the listing after an hour (IIRC) of not getting any re-registration message - this is to avoid the list getting ever longer, since some servers just exist for a short period of time on the same IP.
Oh. wait - the interesting/important bit of your log only got apparent after scrolling down ... the initial bits are perfectly normal - the later bits aren't, it could be that your internet connection was down at the time; more information about your specific setup would be required to give any serious answer though.
I've just checked the masterserver-blacklist - you're not on that; if your other server is registering OK it's indeed mysterious - maybe you started them both so close to each other that they mess with each other in trying to claim the port for registration - try starting them about a minute (or more) apart from each other.
Oh. wait - the interesting/important bit of your log only got apparent after scrolling down ... the initial bits are perfectly normal - the later bits aren't, it could be that your internet connection was down at the time; more information about your specific setup would be required to give any serious answer though.
I've just checked the masterserver-blacklist - you're not on that; if your other server is registering OK it's indeed mysterious - maybe you started them both so close to each other that they mess with each other in trying to claim the port for registration - try starting them about a minute (or more) apart from each other.