由TeamCity触发的构建步骤始终构建 - 即使没有更改

The problem: I am setting up TeamCity as a build server for an ASP.NET MVC project. I am using Powershell with psake to run msbuild against our .csproj file and create a deployable package. From the build server, I can open up powershell, run the script and, because there are no source code changes, msbuild does not regenerate the project DLL files. BUT, when I call the exact same script from the TeamCity web interface, msbuild ALWAYS rebuilds and regenerates the DLL files even though there are no changes. Not what it should do AFAIK. I am setting up TeamCity as a buil