I have also encountered this issue, exactly as Viktor described; loading a quicksave created in lux-b5 produces the "failed to load the saved game" error, but thankfully the autosave produced from the initial transition into lux-b5 is still loadable. Leaving lux-b5 and then trying to re-enter produces the "zone transition failed" error and disables loading of autosaves for lux-b5.
I have no real idea what causes this, but I suspect that it has something to do with the campfire introduced into the zone with the update to v. 1.3.