Reposting Brian Smith’s blog as PPM Works just encountered this when developing reports for a customer. While this was discovered in July of 2016 and was scheduled to be fixed in the Project Server March 2017 CU, it still remains an issue. You will still need to run the script Brian provides in his blog post.
We were not able to recover all the missing views even after running the PowerShell command. Hoping for a permanent fix soon!
Please contact us with questions. We would love to hear from you.