Bug, feature request, or proposal:
Seems the underline is jumping on mat-form-field on focusin and focusout or the thickness is not correct. It looks wierd.
What is the current behavior?

What are the steps to reproduce?
Look at Material Demo Site in Edge Browser
Which versions of Angular, Material, OS, TypeScript, browsers are affected?
MSEdge: 41.16299.15.0
Material: 5.0.0-rc0-3ca801a