Currently there are limitations when converting a task to a project in that critical information isn’t mapped, as noted below:
Attachments, tags, Custom Fields, and comments won’t be copied to your new project.
You can still access this information by following the link to the original task from your new project’s description which is GREAT! However, I’m proposing some automation to occur when this project is going to be added to a Portfolio anyhow.
Since Custom Fields can be applied to a Pipeline (essentially the project level) it would be REALLY nice to have a dropdown option when performing the function to “Convert Task to Project” so that you can select a Portfolio to add the new project to. This will then allow for any matched Custom Fields to map accordingly.