The bug where people cannot join another world, on attempting to join, it just dumps you back to the world list, or freezes.
It is caused by #14 here]http://totalminerforums.net/index.php?topic=608.0]here
The map property corruption bug was caused by errors occuring in the networking code while parsing incoming data sent from other xboxes. It caused the networking code to continue processing packets from the wrong offset in the data, making the data invalid. Some times the networking code thought it was reading map properties, when it wasn't, and there was no safety check to ensure invalid properties weren't used, thereby corrupting the map with bad data.
As part of the fix in 1.9, I put in the safety check, so it would only receive the map properties if the data was valid, and if the data was not valid, it just ignored it.
When you join a map, the host sends the map properties to you. If the hosts map had been affected by the original bug above, some of those properties would have been invalid, so the networking code ignored it. If it was ignored, the connection was not completed, so the world could not be joined.
There are still many maps out there with these invalid properties, so what I'm going to do in 1.92, is if the game detects invalid map properties, it's going to make educated guesses to try and fix the data. If it cannot make an educated guess for a specific property, it will set it to some default. This may cause some maps properties to change, and maybe they will not be what they were originally, but at least they will not be invalid, and players will be able to join the map.