When minting in multiple phases, it's crucial to ensure that all assets are minted by the end. For each phase, specify the number of assets you want to allow except for the last phase (in "Total NFTs available for sale"); leave it blank to permit any additional assets from previous phases to be minted in the final phase. This ensures a seamless completion of the minting process.
NOTE: You will see this "Warning". This is expected and there are no concerns with this when doing this sort of phased mint.