I certainly would not dismiss the possiblity of an error at the factory.

As it happens I am at this moment in the process of giving some tapes one
last chance. They went status=private while last_use is blank because of
problems reading the labels. 90% of the time I can fix that with

checkout libvol mylib problem_vol1 checklabel=no remove=no
checkout libvol mylib problem_vol2 checklabel=no remove=no
label libvol mylib search=yes labelsource=barcode checkin=scratch
overwrite=yes

Nearly always creating a new label like this is sufficient. Of course I keep
an eye on the tape for the next several days, and first sign of any more
trouble I move data from the tape and get rid of it.

Luck!

Kai.