This morning most of my installed Content Packs were no longer listed under My Workspace. When I go to Get Data and click Get It Now to reinstall, I receive an error "We couldn't import data from <report name>. Make sure you are entering information correctly." (Ex: We couldn't import data from Daily Booked Orders..."
One clue could be that there are two content packs that are unaffected by this issue, and the one thing that differentiates them is how they are permissioned. The missing content packs are permissioned via Office 365 groups, whereas one of the two unaffected content packs is published to Entire Organization, and the other has named individuals in the permissions list.