Endpoint "/beta/deviceManagement/configurationPolicies" misbehaves when expanding property assignments for specific policy

Describe the bug

This issue happens ONLY when the targeted policy is of a templateFamily that starts with "endpointSecurity".

I was trying to query the endpoint using the cmdlet:
Get-MgBetaDeviceManagementConfigurationPolicy -ExpandProperty assignments -DeviceManagementConfigurationPolicyId "PolicyID"
and, although the response had the property assignments in the body json, the assignments where empty.

Interestingly, if I query the endpoint without specifying a policy ID (Get-MgBetaDeviceManagementConfigurationPolicy -ExpandProperty assignments), it seems to actually return the data correctly for all the policies.

For the record, I replicated the same scenario in the graph explorer as well

Expected behavior

Expected behaviour would be to actually be able to expand the property assignments even when using the id to target a specific policy

How to reproduce

Execute the command Get-MgBetaDeviceManagementConfigurationPolicy -ExpandProperty assignments
Check that all the policies return the correct assignment data
Execute the command Get-MgBetaDeviceManagementConfigurationPolicy -ExpandProperty assignments -DeviceManagementConfigurationPolicyId "PolicyID"
Check that the returned data do not show any assignments.

Non Working query

Working query

SDK Version

2.28.0

Latest version known to work for scenario above?

No response

Known Workarounds

No response

Debug output

</details>


### Configuration

Name                           Value
----                           -----
PSVersion                      7.5.1
PSEdition                      Core
GitCommitId                    7.5.1
OS                             Microsoft Windows 10.0.26100
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

### Other information

Since this issue is tied to the endpoint not returning the correct data, I believe it is not tied to any of the SDKs. Should be a bug on the backend side,

Start by reproducing the two Get-MgBetaDeviceManagementConfigurationPolicy queries against /beta/deviceManagement/configurationPolicies, using -ExpandProperty assignments with and without -DeviceManagementConfigurationPolicyId. Compare the assignment data for a policy whose templateFamily starts with "endpointSecurity"; done means the targeted query returns the same assignments as the unfiltered query.