There are at least 5 different narratives about how the US found Osama bin Laden, which contradict each other:
https://en.wikipedia.org/wiki/Killing_of_Osama_bin_Laden#Alt...
When a military achieves something and there's intense speculation on how they did it, they will want to obfuscate how they did it. One of the best ways to do that is to give a range of different explanations, some fanciful, some plausible, none of which are completely accurate, leaked to a range of credible and non-credible people. A disinformation campaign.
Despite the authoritarian rule, PRC still values education highly in quite a few contexts where it doesn't interfere too much with the authoritarianism, and the country not only has plenty of physics graduates who will have learned about the Josephson effect, but might well listen to them and give them adequate grants for R&D.