Step 1.
Open a Zendesk ticket to complain so they they are aware of the issue and do something.
(User workarounds no matter how successful result in Asobo never having to address real and existing faults in their code)
Step 2.
Locate the actual file/folder of the content. This will be in a folder named “official” or something.
Rename or delete the file for the missing content. It’s actually there, it just appears to not extract or register properly.
Once you have renamed/deleted the file start the game and you should have the option to download the content in the content manager.