title: Multiple definitions of a property not allowed in strict mode - Angular
body: <p>I ran into this in my Angular (6) project in IE, which caused the app to not load. It only occurred in the prod build of the app, which is concatenated and minified by Angular. The local dev version running under 'ng serve' did not cause the issue. This error was in the Chrome dev console:</p>
  
  <pre><code>SCRIPT1046: Multiple definitions of a property not allowed in strict mode
  File: main.51c74b0704ecaa189364.js, Line: 1, Column: 1263758
  </code></pre>
  
  <p>Here was the location in the minified main script it was referring to:</p>
  
  <pre><code>(6,{"col-6":0,"col-6":1})
  </code></pre>