The re-run after deleting all previous attempts at saving this website went to
completion without any "unexpected 412/416" errors, so the bug remains in
"fixed" condition so long as your ISP doesn't move the target website in the
middle of the saving process. If that has happened, your target files will
have been erased and replaced with new ones, which is what precipitates this
sort of error message. The result is that the saved versions of the files get
hopelessly corrupted. The solution ? Be patient, and give time for the ID
address process to propagate.