User has an overhead project with phases and wants to know why the phases are showing up for billing in the Create Batch Invoice screen with a Net Bill amount.
By default, CORE marks all the time entries logged for an overhead project as non-billable and they do not show up for billing. So it seems you have set the contract type for the phases to something other than Overhead, which causes them to show up for billing because of billable entries. If this is the case, you should update the contract type for each phase to Overhead in the Projects > General > Details screen. CORE prompts you to mark the time and expenses associated with the project to non-billable. Choose Yes to All. CORE makes the entries non-billable and they don't show up for billing.
Note: Projects can also show up in the Create Batch Invoice screen without a Net Bill amount if they have the rule Always show in Create Batch Invoice screen set. Remove this rule if you don't want them to always show up for billing. Check CORE Help Center for details.