Another issue is producers hoarding inputs to the production of consumer goods: commodities (corn, wheat, cotton, steel, oil etc.). An example of this is the chip shortage that we're experiencing. Before, most companies would have maybe a month worth of chip inventory. Now, they'd prefer to have at least a year's worth of inventory of chips, to secure both the chip price and their ability to even obtain them. That's more than a 10-fold increase in the demand for chips over a very short period of time.
When commodity prices rise, the exact same pattern occurs for companies that use commodities as inputs. With falling or constant commodity prices (as we've experienced for the past 10 years [1]), companies have little incentive to have much of an inventory. With increasing commodity prices, the incentive for producers to hoard them is proportional to the rate of increase in their price†. And the more they hoard the more the prices increase, which causes more hoarding etc.
† This is a simplification. Interest rates play an important role here: if the company's annual expected price increase is greater than the interest rate at which they can borrow, then it's profitable for the company to borrow money to buy commodities.