OK, thanks for your persistence.
I was wrong! No changes have been made to your version. I checked mine, yours, and the current download, all the same.
What I discovered is I had neglected to check the JA diplomatics setting, I was only checking West's & GE setting.
Tom I expect never envisioned your course of events. The game allows it to occur because there's settings in the code to change relations: meaning whatever they currently are, make them opposite, and settings for when that occurs, have the territories and units change as well.
Since JA was already at war with West, when Pacific Blitz played, which just says in effect, "make opposite" it had unintended consequences.
In my upcoming WaW Revised version, currently in testing, I've made a lot of changes to events already, but I will try to ensure that the tragedy that befell your game doesn't occur in my upcoming version.
Thanks again for your persistence.