My understanding is that Japan experienced the same kind of phenomenon that is unwinding in the US right now.

As long as your markets and tax policy are vicious enough that lots of normal people can barely make ends meet, you can print as much money as you want and it won't show up on the CPI. Instead, if you funnel that money to rich people, it will show entirely as growth in the price of investment instruments.

At the same time, you will have great economical indicators, and even large taxes that can be spent on anything that doesn't end up on the population's bank accounts (like on infrastructure).

But that money keeps piling up on investment, making them more and more distant from normal cost of life expenses. As soon as any of it reaches normal people, the CPI explodes.