When attempting to Azure-enable an existing User in the Active Roles Web Interface or the Active Roles Management Shell, the operation fails immediately with one of the following errors:
The controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>)
Object reference not set to an instance of an object.
This issue has been tied to setting a value to edsaAzureUserPrincipalName via a custom Property Generation and Validation Policy. As a workaround, instead set the desired value via a Change Workflow.
Waiting for a fix in a future release of Active Roles.