It seems to be exactly the same issue that AlexK fixed last time. Like he suggested, click the “Import” button on the home page, above “My Projects” and all the way on the right side:
Then click “Import URL…”:
Then paste in one of the project links and click “Go Ahead!” and the new project created should have all your code! Obviously repeat for the second project.
This seems to be a glitch that stops happening to shared projects, so the code in the share links is unaffected. Importing the links simply creates a new project with the code not “disappeared”.