I have a form on a page, something simple like:
The problem appears when a form only has input elements without a name
attribute (or no input elements). I found a reference to the bug here, though it also happens in desktop mode and not just metro mode as the link claims:
http://connect.microsoft.com/IE/feedback/details/807447/ie-11-metro-version-submitting-form-fails-if-input-tag-has-no-name-attribute
The fix is to create a dummy field (with a name and value set) before submitting the form.
The bug happens in all compatibility modes offered by IE11.