As per New Amendment Act 31 of 2018 & the was Notified by Notification 2/2019 CT , the High Sea Sale has been brought Under Schedule III, So it's neither treated as supply of Goods nor supply of services.
Note: As per Amendment Act , the section 17(3) of CGST Act it is being clarified that "Value of Exempted Supply" for the purpose of reversal of ITC shall not include the value of activities specified in Schedule III , Except Entry No.5 of said schedule.