Add a visual flag (Like the Note indicator) on the Task line to indicate that an attachment exists.
A note identifier is visible to the user from the TAsk list when a NOte has been added to the item. However, if a File is attached to a Task item, there is no visible way to know unless you view the details of the task.
We added support for this in the new app.
If you are not yet on the new version here is how to get on it: