Perhaps, Japanese government decided to let China know its brand new sub type 093B is already obsolete, and to give humiliation to China. This could be a reasonable decision as a Cost-Imposing Strategy. China was forced to spend huge budget to improve its submarines.
Even we know that already. The 09III family is not an impressive piece of hardware by 2018 premiere standards. Koda's statement sounds less like an intelligence leak and more of a publicity stunt.
Perhaps, Koda knew PLAN was overconfident on acoustics of type 093B.
Yeah, and Xi Jinping has the blueprints to the entirety of the Asahi-class. Use your critical thinking and start evaluating the likelihood of your propositions.