Allo,
Bungie are aware and investigating but have stated not to worry. When it comes to moving to steam, all licences purchased will move over.
[quote][b]Displayed Account Licenses:[/b] We’ve observed reports indicating that not all [i]Destiny 2[/i] content licenses are being shown to players when preparing for PC migration. Players can dismiss this prompt, which may sometimes report an incomplete list of game licenses. All owned licenses will be transferred with PC migration later this year.
[/quote]
https://www.bungie.net/en/Forum/Post/253269781/0/0