vscode-csharp: Build error during preLaunchTask 'build'.

Whenever I press F5 to debug an RC2 ASP.Net app, I get the following error in a bar along the top:

Build error has been detected during preLaunchTask 'build'.

with a ‘Debug Anyway’ and ‘Close’ option.

I encounter the issue every time.

Build outputs associated with this:

Project Project.Omega (.NETCoreApp,Version=v1.0) will be compiled because Input items removed from last build
Compiling Project.Omega for .NETCoreApp,Version=v1.0
Compilation succeeded.
    0 Warning(s)
    0 Error(s)
Time elapsed 00:00:01.3013499

Project Project.Omega (.NETCoreApp,Version=v1.0) was previously compiled. Skipping compilation.

VS Code:

[Window Title]
Visual Studio Code - Insiders

[Main Instruction]
Visual Studio Code - Insiders

[Content]

Version 1.1.0-insider
Commit c212f0908f3d29933317bbc3233568fbca7944b1
Date 2016-05-09T13:09:51.092Z
Shell 0.37.6
Renderer 49.0.2623.75
Node 5.10.0

omnisharp-vscode package: csharp-1.0.5-rc2.vsix

In the project, I’m using Microsoft.NETCore.App version 1.0.0-rc2-3002700.

Debug Anyway works, but it’s a pain to have to click that every time.