User-defined type error for ARM template modules

[shenglol]

Bicep version
v0.20.4

Describe the bug
Got a type error when assigning a value to a deeply nested property of a parameter whose type is user defined. The error does not happen if the reference module that contains the user defined type is a Bicep file. However, it happens if the module reference is the compiled ARM template file. The bug was found in a public registry PR: Azure/bicep-registry-modules#440.

To Reproduce
Here's a minimal setup that reproduces the issue:

• mod.bicep

type partitionKeyTypeForSqlContainerAndGremlinGraph = {
  kind: 'Hash' | 'MultiHash' | 'Range'?
}

type sqlContainerType = {
  partitionKey: partitionKeyTypeForSqlContainerAndGremlinGraph?
}

type sqlDatabaseType = {
  containers: sqlContainerType[]?
}

param sqlDatabases sqlDatabaseType[] = []

• main.bicep

module mod 'mod.json' = {
  name: 'mod'
  params: {
    sqlDatabases: [
      {
        name: 'foo'
        containers: [
          {
            partitionKey: {
              kind: 'Hash' // The property "kind" expected a value of type "error | null" but the provided value is of type "'Hash'".
            }
          }
        ]
      }
    ]
  }
}

Additional context
Add any other context about the problem here.