As of when I posted above all has been as hitherto. I had emptied my Safari cache for other reasons before the Sad Mac episodes began. Now that connection to 68kmla has been re-established, the same bookmarks et alia as before function flawlessly, so I have no credible explanation of the phenomenon. Nor has my ISP been suspicionable, in this instance at least. The episode was just another Murphyism, it seems.

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