"Reflect is undefined" error on IE11 at Meteor 1.6.1

When I updated my app, which worked fine at Meteor 1.6.0.1, to Meteor 1.6.1, it works fine on the latest browsers, but it does not work on IE11.

The error is “Reflect is undefined” in modules.js, and I found that omega:custom-protocol is related with the error.

I am confused because omega:custom-protocol seems not use Reflect.

What happens at Meteor 1.6.1?