I always like when some people generate a fast-stamped answer by keywords, without reading into the thread:
"Nuked areas" + "fix" = "The nuked areas can't get fixed since there is no back up of what they looked like before."
Now, nuked areas can be 'fixed'.(reverted to non-nuked) By filling it with Any landscape.(a megatile of dirt, for example) And that would remove the quarantine zone as well, allowing the OP to cross the line and walk into his house. Nuked(missing) area of the map is a lot farther into quarantine area, and cannot be rendered. Distance of locked down non-nuked land is grater then you can scroll the map to prevent a server-crashing render attempt.
And ofcourse by "can be" i never mean "will be".
And, Burgingham, please, dont take it as an offense, but you have a habit keyword-answering. You also often lock a thread afterwards, and no one can counter argue.
Last time it was here ("leaving"+"middle of a river"+"boat has disappeared"), whilst the OP meant that a christ-like water walking(standing) seems like a bug to him. :p
(though its more of a feature)