Before closing a task that is waiting on another task, ClickUp can display a warning message to ensure you aren't missing anything.
You have the power to enable (and disable) this warning at any time.
How to enable (or disable the warning)
As an admin, you have the ability to adjust this warning on a Space level:
Visit your Settings page.
Click the ClickApps item in your left-sidebar.
Locate the Dependency Warning ClickApp.
Select which Spaces to enable (or disable).