If your domain is set to track the same set of keywords in Rank Intelligence and Visibility Share, and you recently deleted keywords from your Rank Intelligence managed keywords, those keywords are also going to be deleted in Visibility Share. This is because they are under the same set of tracked keywords, so if a keyword is deleted in Rank Intelligence, they are deleted from being rank tracked on both Rank Intelligence and Visibility Share

Where's the historical Visibility Share data for deleted keywords?

You can view historical data for a keyword that you were tracking in Visibility Share by unchecking the "Ignore Deleted Keywords" filter.