Need help figuring out what this Ember unloadAll does

I have this route that currently, when I transition back to it, gives me this great big error with a stack trace that doesn't help me figure out what is going wrong.

Error while processing route: project.details Assertion Failed: calling set on destroyed object Error: Assertion Failed: calling set on destroyed object at new Error (native) at Error.EmberError (http://ift.tt/1jDSJnk) at Object.Ember.default.assert (http://ift.tt/1NJLaIZ) at Object.set (http://ift.tt/1jDSJno) at exports.default.mixin.Mixin.create.set (http://ift.tt/1NJLcAD) at Ember.Object.extend.flushCanonical (http://ift.tt/1jDSLM3) at ember$data$lib$system$relationships$state$has_many$$ManyRelationship.flushCanonical (http://ift.tt/1NJLcAG) at Queue.invoke (http://ift.tt/1jDSLM5) at Object.Queue.flush (http://ift.tt/1NJLaJ7) at Object.DeferredActionQue

Through just going through my routes and commenting out stuff, I found this in my projects route:

export default Ember.Route.extend(AuthenticatedRouteMixin, {
  model: function(params) {
    if (params.q) {
      return this.store.find('project', params);
    } else {
      var _this = this;
      Ember.run(function() {
        _this.store.unloadAll('project');
      });
      return this.store.findAll('project', {reload: true});
    }
  }

And if I comment out lines 7-9:

/*
  Ember.run(function() {
    _this.store.unloadAll('project');
  });
*/

then the error goes away and the transition worked. This bit of code was written by somebody else, and I think it has to do with refreshing the model from the store, but I can't figure out why it would cause this "calling set on a destroyed object" error.

Any help would be greatly appreciated.