This is only a demonstration to reproduce the error.
In a real project I have a shader where this error occurs as a consequence of the optimization calculations for certain values of the input data (like landscape layer weights).
I have gone ahead and entered a bug report for this issue, UE-31792. Once the issue has been addressed by our engineers it will be added to a our known issues for an upcoming full engine release or hotfix.
Let me know if you have further questions or need additional assistance.