Some good catches there.
We all know that Alembic hum canceling pickups are not humbuckers, and the writer perhaps wasn't aware of the distinction (or didn't want to get off topic by explaining). But someone will get in an argument and insist "no, they were humbuckers, it says so right here in Bass Magazine."
The picture that mislabels the hum canceler as a quad pickup looks like it might be from somewhere else and a fairly recent edit. The writer may have simply accepted it as authoritative, or may not have read it for details like that. I didn't notice it until it was pointed out.
I imagine that, besides incorporating newly uncovered facts into history, historians consider it important to make sure that the old, well-established facts are not lost or corrupted.