The article states similar coordinated currency manipulation (to instead weaken the yen) happened in 2011 after the Tohoku earthquake. There was a bunch of mutual currency manipulation in the 1990s by the US and Japan.[1] In the 1980s there was the Plaza and Louvre accords. [2][3] And you can find more going all the way back to end of World War 2.
The main interesting difference in the current intervention is that the US is selling euros (not dollars) to buy yen.
[1] https://www.nber.org/papers/w8914
Difference is US now has its own issues which just makes the overall situation even more fragile.
No one knows for how long or what happens next, but you can’t look at things and think, eh it’s just the way it is. Things are a certain way until they’re not