TeamCity build (MSBuild) is adding erroneous line breaks to transform

[kcoderhere]

Using SlowCheetah version 2.5.14 from NuGet.

My app.config looks something like this:

<configuration>
  ...
  <applicationSettings>
    <MyProgram.Settings>
      <setting name="ApiUrl" serializeAs="String">
        <value>http://www.test.com/api/</value>
      </setting>
    </MyProgram.Settings>
  </applicationSettings>
</configuration>

My Release transform looks like this:

<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform">
  <applicationSettings>
    <MyProgram.Settings>
      <setting name="ApiUrl" serializeAs="String" xdt:Transform="Replace" xdt:Locator="Match(name)">
        <value>http://www.production.com/api/</value>
      </setting>
    </MyProgram.Settings>
  </applicationSettings>
</configuration>

In Visual Studio, the output works correctly and looks like this:

<configuration>
  ...
  <applicationSettings>
    <MyProgram.Settings>
      <setting name="ApiUrl" serializeAs="String">
        <value>http://www.production.com/api/</value>
      </setting>
    </MyProgram.Settings>
  </applicationSettings>
</configuration>

When building using TeamCity and MSBuild, the config transforms but it looks like this, adding a line-break and several spaces to the end (which causes errors with some settings that are looking for an int or bool or file path name):

<configuration>
  ...
  <applicationSettings>
    <MyProgram.Settings>
      <setting name="ApiUrl" serializeAs="String">
        <value>http://www.production.com/api/
        </value>
      </setting>
    </MyProgram.Settings>
  </applicationSettings>
</configuration>

What could be causing this?