Strikethrough equipment appears in your project when an item that was previously planned is no longer available in your equipment database.
This can happen, for example, if you create a project template that includes an item and you archive that item later. When you use the template to create a new project, the archived equipment still appears in the equipment list of your project but is displayed with a strikethrough since it no longer exists in your database.
To resolve this, create a new project without the archived equipment and in the settings Configuration module use it to create a new project template.