Flow Error: 'Maximum number of duplicate updates in one batch (12 allowed)'

When Does the 'Maximum number of duplicate updates in one batch' Error Occur?

This error occurs when multiple duplicate scheduled actions — such as waiting interviews — are created for the same record, exceeding the maximum of 12 duplicate record updates allowed in a single batch in Salesforce Flows.
For example, this can occur when using the Bulk API to make a large number of updates to the same record simultaneously, triggering a Flow that contains a Wait element. Salesforce batches actions scheduled to occur at the same time, as described in the Transactions and Scheduled Actions documentation: "Scheduled actions aren't performed independently. They're batched together with other actions that are scheduled to execute at the same time."