When modifying the VIP configuration file imported from Fortigate on Fortimanager, prompt 'Map to IP

When modifying any content in the VIP configuration file imported from Fortigate on Fortimanager, clicking the confirm button prompts Map to IPv6 Port This field is required. However, Fortigate does not actually enable IPv6. If using the VIP configuration file created from Fortimanager, this phenomenon does not occur. Fortimanager version is 7.4.5