Budget items might not appear in the project allocation if the project is in the Draft status. In BQE CORE, Allocation & Forecasting is designed to display data primarily for active projects. When a project is in Draft status, its budget items are hidden by default and are not automatically listed after copying a budget.
You can view these items by selecting More > Show All in the Allocation & Forecasting screen, or by changing the project status from Draft to an Active status. After the project is active, all copied budget items display as expected and are fully available for allocation and forecasting.