This happens when people are "informed" by old discarded ideas, who then do nothing to check it. It is very common with beads.

I addressed this in my paper for The Glass Trade Bead Conference, and the articles I composed for Ornament in 1983.

In the briefest terms possible. 100+ years ago, when archaeology was still in its formative years, two things were put together. It was understood that the the Egyptian culture was very old, that "glass was invented there" (not actually true!), and that Egyptians made glass beads. They also knew that impressive (conventional) seven-layer chevron beads were recovered in Egypt--and it was presumed that these might have been ancient. Circumstantially, in the 1920s, when old chevron beads were compared to new Venetian chevron beads, the similarity was strong. The new beads were new--and the old beads were old. But no one knew how old; and no one (in a position to have some perspective on Venetian history) knew when Venetians pursued this work.

Even in Beck's time (1928) this was still a question--though ideas countering it were voiced, that early chevron beads were antique but not ancient.

In 1981 I made a point to go to Cambridge to see the Beck collection. I was thereafter convinced that this was a matter of mistaken identity, based on ignorance, and simple wishful-thinking. And, according to my research and piecing-together of Venetian history, I affirmed that rosetta beads were devised by Angelo Baroviero, in the mid-to-late 15th C. And I am confident he also devised drawn glass beads in-general.

However, in every decade since the 1960s (when I began with beads), someone has published the misinformation that "chevron beads were ancient." I have multiple expositions discussing and challenging all this. Even here at the Forum.