From the U.S. Federal Reserve:
Business and bank closures associated with the COVID-19 pandemic have significantly disrupted the supply chain and normal circulation patterns for U.S. coins. While there is an adequate overall amount of coins in the economy, the slowed pace of circulation has reduced available inventories in some areas of the country.
The Federal Reserve is working with the U.S. Mint and others in the industry on solutions. As a first step, a temporary cap was imposed on the orders depository institutions place for coins with the Federal Reserve to ensure that the current supply is fairly distributed. In addition, a U.S. Coin Task Force was formed to identify, implement, and promote actions to address disruptions to coin circulation.
As the economy recovers and businesses reopen, more coins will flow back into retail and banking channels and eventually into the Federal Reserve, which should allow for the rebuilding of coin inventories.