Protractor `addMockModule()` with arguments not ha

I recently read about the solution for these protractor issues:

Unable to easily pass context to addMockModule #695
feat(addMockModule): add third parameter to pass context #787

I have been eager to DRY up my protractor tests and this was the solution I needed. This solution is working great with ChromeDriver, but with FirefoxDriver it's oddly broken. Here's my code (in a beforeEach() block:

  var httpBackendMock = function() {
      angular.module('httpBackendMock', ['ngMockE2E'])
        .value('mockData', arguments[0])
        .run(function ($httpBackend, mockData) {
          $httpBackend.whenGET(/.*aggregates/)
            .respond(200, mockData.testAggregates);
          $httpBackend.whenGET(/.*merchants\/123456/)
            .respond(200, mockData.testMerchant);
        });
  };
  browser.addMockModule('httpBackendMock', httpBackendMock, {
    testAggregates: testAggregates,
    testMerchant: testMerchant
  });

(testAggregates and testMerchant are defined previously.)

This works perfectly in Chrome, but in Firefox when the whenGET expectations fire they return no data. It fails whether I use the mockData object or directly use arguments[0].

But it gets weirder. If I try to inspect the mockData module value I created above in a later browser.executeScript() call, the data is there, and console.log renders it the same way in both Chrome and Firefox.

  browser.get('index.html#/experiments');
  browser.executeScript(function() {
    return angular.injector(["httpBackendMock"]).get('mockData');
  }).then(function(data) {
    console.log("DATA", data);
  });

When the test runs the data shows up as expected.

The only workaround for this I have found is to JSON.stringify() the input to addMockModule() and JSON.parse() it inside. It seems to work, but is ugly - the framework should already be taking care of it.

So I think this is a bug, but I'm really not sure which component this is a bug in.