Bicep template, user managed identity not added to app service slot, no errors

I have created an Azure bicep template to deploy a new slot to an existing app service.

There is also an existing user managed identity I would like added to the new app service slot so it can access some key vault secrets.

I have tried a few different variations of this template with no luck on getting the user managed identity to be assigned via the bicep template.

I can successfully add the user managed identity, manually, after the bicep deployment has finished. There are no errors generated from the deployment.

Below is my template:

@description('Name of the api to add the slot.')
param apiName string

@description('Name of the slot.')
param slotName string

@description('Name of the location of the existing api.')
param locationName string = resourceGroup().location

@description('Name of the managed identity to assign to the slot.')
param managedIdentityName string

resource apiParent 'Microsoft.Web/sites@2018-11-01' existing = {
  name: apiName
}

resource uami 'Microsoft.ManagedIdentity/userAssignedIdentities@2018-11-30' existing = {
  name: managedIdentityName
}

output uamiId string = uami.id

resource apiDeploymentSlot 'Microsoft.Web/sites/slots@2022-03-01' = {
  name: slotName
  parent: apiParent
  location: locationName
  identity: {
    type: 'UserAssigned'
    userAssignedIdentities: {
      '${uami.id}': {}
    }
  }
  properties: {
    serverFarmId: apiParent.properties.serverFarmId
    cloningInfo: {
      sourceWebAppId: apiParent.id
    }
    keyVaultReferenceIdentity: uami.id
  }
}

And some screenshots of the deployment:

And the output from the bicep template shows the existing user managed identity was found.

But there is no user managed identity after the deployment finishes.

Any ideas?

I have tested the above shared template in my local if we remove the cloning info block, we are able to create a new deployment and attach the user assigned managed identity without any issues.

If cloning info block is present in the template, it is ignoring the entire payload. Request you to remove the cloning info property and retry the deployment.

Refer to this similar thread here.