It will be necessary to test another SSD on the NUC in order to find out if the Msata is or not defective.
If the issue persisted, if will be necessary to replace the whole unit since we do not have spare parts.
If you want contact our warranty team, please submit a web ticket to request an RMA
https://servicerequestmgmt.intel.com/webticketui/emailpage.aspx?lang=en-us.