This article explains which data types ProBackup can restore for Asana and any known limitations.
Projects
When you restore a project, a new project is created in the workspace. All tasks, comments, files, and custom fields are restored with it.
Due to API restrictions, the following field types cannot be restored and will be skipped:
Formula fields
Read-only computed fields (any field with IsValueReadOnly = true)
Tasks
When you restore a task, a duplicate is created in the related project. All comments, files, and custom fields are included.
Comments
When you restore a comment, a duplicate is created in the related task.
Files
When you restore a file, it is added to the related task.
Custom fields
When you restore a custom field, a duplicate is created in the related project. All field values for existing tasks are restored as well.