Conventional explanations include "price stickiness": wages and prices don't change overnight, they have to be deliberately changed by individuals in the market. And the more technical "transmission mechanism": just as an automatic transmission doesn't immediately convert faster engine RPM into faster road speed, there is substantial lag in the mechanisms by which money production affects prices.
The reverse process was seen round about the introduction of the Brazilian "Real". People had become used to inflation and re-negotiating prices regularly. Swapping out the name of the currency helped reset that in the minds of the public. https://en.wikipedia.org/wiki/Plano_Real
One of the more convincing ideas is that, because fiscal policy is either conservative or only expansionary for high earners, monetary expansion doesn't affect most consumption prices and only affects assets. e.g. house prices and the stock market.
No one - who's talking at least - seems to understand what's going on with this. It's uncharted territory in a world economic system way more complex than when text books were written.
I have to think fundamental reality must catch up sooner or later, possibly unravelling in a sudden crash.
Then again, I do not understand this!