nuget content/contentfiles are duplicated in nested nuget package

I have 3 projects which are nested in each other.

1. HtAlarms.Common

   • Has a configuration file HtAlarms.config
   • A nuget package is created from this: HtAlarms.Common.nuget

2. HtOpc.Alarms

   • Contains the HtAlarms.Common.nuget package
   • A nuget package is created from this: HtOpc.Alarms.nuget
     • HtAlarms.config is wrongly included in the nuget-package!
3. HtServer.ServerTemplate
   • Contains the HtOpc.Alarms.nuget package

     - HtAlarms.config is wrongly included in the root directory!

HtAlarms.Common has the following directory structure:

+-- Config
|   +-- NLog
|   |   +-- HtAlarms.config

HtAlarms.Common.csproj

...
  <ItemGroup>
    <Content Include="Config\NLog\HtAlarms.config">
      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
    </Content>
  </ItemGroup>
...

HtOPC.Alarms has the following directory structure:

+-- Config
|   +-- NLog
|   |   +-- HtAlarms.config

HtOPC.Alarms.csproj

...
  <ItemGroup>
    <PackageReference Include="HtAlarms.Common" Version="6.0.0-fix-htalarms-config.68" />
  </ItemGroup>
...

But the nuget package has already a duplicate!?

HtServer.ServerTemplate has the following directory structure:

+-- Config
|   +-- NLog
|   |   +-- HtAlarms.config
+-- HtAlarms.config

HtAlarms.Common.nuget installs Config/NLog/HtAlarms.config - Right

HtOPC.Alarms.nuget installs HtAlarms.config - Wrong

Also CopyToOutputDirectory is false. Should be true.

Someone can tell me what's wrong here? Thanks!!