Grunt shell is messing up slashes and colons

Question

I'm using grunt (v0.4.5)and grunt-shell on windows7 for executing a curl command. Got some problems with that.

The plain curl "dev.machine.com/caches/dependency/clear on the command line works fine.

grunt-shell config part:

          shell: {
            resetCaches: {
               command: 'curl "dev.machine.net/caches/dependency/clear"',
               options: {
                  stdout: true,
                  stderr: true,
                  stdinRawMode: true,
                  failOnError: false,
                  execOptions: {
                     maxBuffer: "Infinite"
                  }
               }
            }
          }

Executing the same command via grunt shell:resetCaches breaks everything.

Error message: curl: (6) Could not resolve host: dev.machine.net\caches\dependency\clear

Somehow the slashes became backslashes. But why?