Upon killing the CSC Antarctica, it will come back from the dead every time the player reenters the system.

This glitch is caused by OnGlobalSystemStarted block starting at line 242 of Antarctica02.xml. It appears to spawn the Antarctica in any case where msEscapeFromDantalion has not been completed and the system being entered is Dantalion. This mission appears to only occur if the player sides with the Antarctica.

I'm not sure I understand why the structure here behaves as it does - it may make more sense to set up the Antarctica situation as a single mission, similar to how it was structured before, unless it's expected to be lengthened significantly later on. It's also worth noting that the case in which the Antarctica spawns in the CSC Terra's system rather than in Dantalion appears to have been done away with, in case this isn't intentional.