Searching for more information, I came across this two-months-older article:

> The Atomki group has produced three previous papers on their beryllium-8 experiments — conference proceedings in 2008, 2012 and 2015.

> The first paper claimed evidence of a new boson of mass 12 MeV, and the second described an anomaly corresponding to a 13.45-MeV boson. (The third was a preliminary version of the Physical Review Letters paper.)

> The first two bumps have disappeared in the latest data, collected with an improved experimental setup. “The new claim now is [a] boson with a mass of 16.7 MeV,” Naviliat-Cuncic said. “But they don’t say anything about what went wrong in their previous claims and why we should not take those claims seriously.” One naturally wonders, he said, “Is this value that they quote now going to change in the next four years?”

[0] https://www.quantamagazine.org/20160607-new-boson-claim-face...