title: Possible bug affecting Edge 86, Dojo, ArcGIS Javascript 4.xx
body: <p>We have an application that has been running for several months that leverages ArcGIS Javascript api 4.xx. When the application loads the map control is initialized using a dojo.require function:</p>
  <p>require([
  &quot;esri/Basemap&quot;,
  &quot;esri/Map&quot;,
  &quot;esri/views/MapView&quot;,
  &quot;esri/layers/MapImageLayer&quot;,
  &quot;esri/layers/FeatureLayer&quot;
  ], function (Basemap, Map, MapView, MapImageLayer, FeatureLayer)...</p>
  <p>Suddenly, late last week or early this week (around 11/16/2020) when the page first loads the map does not appear and the DevTools console shows the error: <strong>Uncaught (in promise) ReferenceError: require is not defined.</strong></p>
  <p>Pressing F5 refreshes the page and then the map loads normally. But if I close the browser and navigate to the application again the same behavior; it errors on the first load but it works on a refresh.</p>
  <p>Interestingly, this appears to be limited to Edge (I'm running 86.0.622.69 which was released on 11/13). I have not been able to repro the problem on either Chrome or Firefox. As I mentioned this application has been under development for over a year and running in a production environment for several months. No changes to the mapping code have been made for quite a while. Edge is the browser I normally use while developing.</p>