"mitigation" to me means that there were issues found which they now belive they have lessened, but not completely removed (ie whatever issue there was might still occur, but only in extreme circumstances and therefore at an acceptable low probability).
It says the conformation testing is scheduled for September 25, not that it is x weeks starting September 25. So sounds like this is just a quick check eg testing chemical composition to ensure it is within specs not something that needs to be run through repeated cycles.
On the positive side:
Unless I have missed it I don't think I'd seen mention of the NDA before
https://global.kawasaki.com/en/mobility/Kawasaki:
* Manufacture Helicopters (target for both CVM and AEM)
* Manufacture cargo and long range patrol aitcraft for JSDAF
* Manufacture sections of fuselage for Boeing 787 and 777 series
* Manufacture sections of Embraer 170/175 and 190/195 series
* Manufacture heavy transport ships (always thought freight ships should be a target market too)
Meanwhile, Subaru
https://www.subaru.co.jp/en/outline/about/aerospace/* Manufacture Helicopters (target for both CVM and AEM)
* Manufacture long range patrol aitcraft for JSDAF
* and...
"Since first participating in the Boeing passenger program in 1973, we have been involved in development and production as a key partner of Boeing for more than 40 years.
Subaru manufactures the center wing box, the critical aircraft section where the right and left wings are attached to the front and rear fuselage sections. Since the center wing box contains the fuel, it needs to be incredibly strong and watertight. For these reasons, great accuracy and advanced assembly technologies are required for its manufacture, and Subaru is one of the few companies capable of making it.
Th
e Handa Plant, located in Aichi Prefecture and where center wing boxes are manufactured, is a global-level production center that produces these parts for the Boeing 777X as well as for the Boeing 777 large airliner, the Boeing 787 mid-size airliner, the Ministry of Defense’s P-1 maritime patrol aircraft, and the C-2 transport aircraft."
(20min delay)