As ishikusui mentioned, licenses are not part of your save data and are not controlled by Bungie. You pay the platform for a license to access the expansion on their platform, so if you change to a different platform, that previous platform's license doesn't go with you. For example, if you paid Microsoft for access to the DLC on Xbox, it's a Microsoft Xbox license, so if you are now playing on Steam, Epic, or the Microsoft PC Store version, you'll need to buy a license for access on that platform, as it's a different license controlled by that platform's system.