Debug pie graph goes to 100% unspecified. Creates lag.

After logging into my multiplayer server, the pie graph goes to 100% "unspecified". This seems to occur after a random interval of between 30 seconds to 5 minutes. This switch happens immediately without first growing in percentage (normal pie graph goes immediately to 100% unspecified). There are NO log reports for the multiplayer server.

This seems to generate lag. This may not be limited to multiplayer. When I leave my server and go to single player, the 100% unspecified persists. HOWEVER, I cannot recreate the bug starting in single player.

When I exit the client and restart, the graph goes back to normal and the process repeats.