How do I script in a date?

In my script I'm trying to take the date the record is created, add 10 years to that value and set it in another field. I have tried a number of ways to achieve this and all of them keep returning errors.

In the image below, highlighted are the logs of the 3 ways I have attempted to update the field. The second one appears perfect but still no luck.

This is the unedited version that will return: Tue May 16 2034 00:00:00 GMT-0700 (PDT)

// Calculate the expiration date for the warranty (current date + 10 years)
var currentDate = new Date();
var expirationDate = new Date(currentDate.getFullYear() + 10, currentDate.getMonth(), currentDate.getDate());

// Log the expiration date
  log.debug('Expiration Date Attempted to Set: ' + expirationDate);

// Save warranty record
  warrantyRecord.save();