Microsoft.WebApplication.targets + Disable_CopyWebApplication=True doesn't prevent a csproj from creating a _PublishedWebsites folder - asp.net

Question

Got a dummy project + a console project which apply xslt transformations so they employ Microsoft.WebApplication.targets in their respective .csproj files like so:
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
<PropertyGroup>
<Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
<Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
<ProjectGuid>{39560935-7551-4789-9666-4A48AD0FE3C7}</ProjectGuid>
<OutputType>Library</OutputType>
<RootNamespace>...</RootNamespace>
<AssemblyName>...</AssemblyName>
<TargetFrameworkVersion>v4.7.1</TargetFrameworkVersion>
<FileAlignment>512</FileAlignment>
<AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
**<Disable_CopyWebApplication>True</Disable_CopyWebApplication>**
</PropertyGroup>
[...]
<PropertyGroup>
<VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">10.0</VisualStudioVersion>
<VSToolsPath Condition="'$(VSToolsPath)' == ''">$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)</VSToolsPath>
</PropertyGroup>
<Import Project="$(VSToolsPath)\WebApplications\Microsoft.WebApplication.targets" Condition="'$(VSToolsPath)' != ''" />
<UsingTask TaskName="TransformXml" AssemblyFile="$(VSToolsPath)\Web\Microsoft.Web.Publishing.Tasks.dll" />
<Target Name="BeforeBuild">
<Exec Command=".\.nuget\nuget.exe restore .\packages.config -PackagesDirectory .\..\packages" />
<Delete Files="Config\ConnectionStrings\ConnectionStrings.config" />
<Message Text="=====================================================================================================================================================" />
<Message Text="Applying XSLT transformations (Disable_CopyWebApplication='$(Disable_CopyWebApplication)') using 'Microsoft.WebApplication.targets' from:" />
<Message Text="" />
<Message Text="$(VSToolsPath)\WebApplications\Microsoft.WebApplication.targets" />
<Message Text="" />
<TransformXml Source="Config\ConnectionStrings\ConnectionStrings.base.config" Transform="Config\ConnectionStrings\ConnectionStrings.$(Configuration.Replace('dbg#', '').Replace('rls#', '')).config" Destination="Config\ConnectionStrings\ConnectionStrings.config" />
<Message Text="=====================================================================================================================================================" />
</Target>
To generate production builds for said projects in our build server we build them like so:
<MSBuild Projects="$(_solutionFile)"
Targets="$(TargetProject)"
Properties="Platform=$(Platform);OutputPath=$(PublishUrl);Configuration=$(Configuration);"
ToolsVersion="15.0"
/>
As shown above we employ
<Disable_CopyWebApplication>True</Disable_CopyWebApplication>
Still the _PublishedWebsite folder does get created anyways. What could we be missing here?
UPDATE
According to the debugging statements we placed in our .csproj file the "Microsoft.WebApplication.targets" which gets employed during the build is this one:
"C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\MSBuild\Microsoft\VisualStudio\v15.0\WebApplications\Microsoft.WebApplication.targets"
The internal task which copies the "website" (exe in our case) is this:
<Target Name="_CopyWebApplication"
Condition="!$(Disable_CopyWebApplication) And '$(OutDir)' != '$(OutputPath)'"
DependsOnTargets="$(_CopyWebApplicationDependsOn)">
<CallTarget Condition="'$(OnAfter_CopyWebApplication)' != ''" Targets="$(OnAfter_CopyWebApplication)" RunEachTargetSeparately="true" />
</Target>
This task appears to be working as intended because it turns out that _PublishedWebsite doesn't contain any of the compiled dlls of the exe-project. It contains only the roslyn dlls/exes with the following folder structure:
<Project_Output_Folder>\_PublishedWebsites\<Project.Name.Here>\bin\roslyn
I take it that the inclusion of the nuget packages:
Microsoft.Net.Compilers
and/or
Microsoft.CodeDom.Providers.DotNetCompilerPlatform
is what's causing the problem. The nuget packages being used are these:
<?xml version="1.0" encoding="utf-8"?>
<packages>
<package id="EntityFramework" version="6.2.0" targetFramework="net471" allowedVersions="[6.2.0]" />
<package id="Microsoft.CodeDom.Providers.DotNetCompilerPlatform" version="1.0.8" targetFramework="net471" allowedVersions="[1.0.8]" />
<package id="Microsoft.Net.Compilers" version="2.6.1" targetFramework="net471" developmentDependency="true" allowedVersions="[2.6.1]" />
<package id="Newtonsoft.Json" version="10.0.3" targetFramework="net471" allowedVersions="[10.0.3]" />
<package id="Oracle.ManagedDataAccess" version="12.2.1100" targetFramework="net471" allowedVersions="[12.2.1100]" />
<package id="Oracle.ManagedDataAccess.EntityFramework" version="12.2.1100" targetFramework="net471" allowedVersions="[12.2.1100]" />
<package id="StructureMap" version="4.6.1" targetFramework="net471" allowedVersions="[4.6.1]" />
<package id="System.Reflection.Emit.Lightweight" version="4.3.0" targetFramework="net471" allowedVersions="[4.3.0]" />
</packages>
So I guess the question boils down to how can one make the Compilers package respect the dont-copy flag we are setting?