Total economic and cultural breakdown
The initial part will be bad. People are used to a certain way and this will completely break it.
Why? Economic value cannot be trusted. Gold and other valuable materials can become four times its original volume. But the energy sector as well. You can use four times as much gas, or get four times the use out of coal. Other things will reduce in value and costs. The whole chip industry can make high end chips and create four copies. All that is needed is the time and personnel for the spell. This might not be viable in all cases with large volumes like gas, but certainly on a personal level it makes sense to duplicate your tank of gas, or copy your phone if it's thin enough to have the mass of a candybar.
Worse even are duplication loops. Even just copying your food can change the world. Not alone because it can end world hunger. You copy food, shit it out, which you duplicate to fertilise a field, which grows into food, which you duplicate, which might be baked and thus transformed, which can be duplicated, which is eaten..... whole industries to copy can be created.
It doesn't mean the end of civilization. A crisis is the biggest motivator for change. The population might go through an uncomfortable period with devaluation of many products and materials. But if people adapt, it can be a large boon to the society. They can rebuild with the new outlooks on values and use cases. Products might form to specifically allow duplication or prevent it. Services and automation become more important. It leads to a more utopian society with abundance.
That is of course if people can let go of the old and get some agreements on the new. The society might collapse outright, leading to so much unrest that the society will tear itself apart. It is strange to think that with sudden abundance for everyone, they can start fighting.
The time can really differ. Looking at Corona, a societal change, we can see that most were already 'comfortable' with the change after a year. I'm not saying this change was sustainable, but it was largely accepted. That means after a year, people might already be comfortable with the change. However, it really depends on the unrest created by also media and such. We can see that regardless of what is happening, media can twist or fabricate a lot to their will. This can influence to acceptance or rejection. This in turn can lead to total collapse, taking decades to recover. It can lead to unrest, but creative solutions and the abundance, especially for the "common man", can lead to a divide in society that can take years to mend. Or the first one, that media and abundance can reduce the unrest to such an extent that a year is all that's needed for widespread acceptance.
What is more interesting to me is how much extra mass can be created. If the full population just copies its food every day, how long until the abundance of these carbohydrates and the like do something interesting to the ecology? How long until it influences the Earthbin a tiny, but significant, bit by just added mass?