Symptoms
When trying to deploy a package the user was receiving the following error:
System.NullreferenceException
SmartObject property PackageFile is a required property for selected method LoadPackage. FileName property must be set.
Diagnoses
This is a known an tracked issue that happens in clustered Appit environments. The cause here is a desync causing a SmartObject to execute before the required inputs are set.
Resolution
Redeploying the package tends to be enough to correct the issue.