I think I would argue that it is easier to speculate as to the who, than how it works. In 1930s, no one was thinking super polymers printed on a 3d printer at molecular levels, and so consequently- they would have never figured a thing out, just as a caveman would never backwards engineer a cell phone by busting it into its constituent parts.

If the five observables result in scientists completely ignoring this as 'paranormal' since the 1940s, it's because they thought it was too magically woo to be real. Now, thanks to years of science fiction saying warp drive is real, the world finally has a box to place it in. But whether it's now, or 1940s, this stuff is behaving in ways that was thought completely impossible to such a degree it's reasonable to interject a non-human presence. There were drones in the 1940s flying alongside Allied and Axis aircraft.