Required text inputs show as valid even if the user just clicks in and out of the field.

[pixelbandito]

You can see this happening on http://demo.dsheiko.com/html5formshim/, by inspecting the first "Name" field.

It happens in IE8 on Windows XP and on Chrome 28 on Mac OS X, so I expect it happens everywhere.

As a side note, since this is a polyfill / shim, it probably shouldn't be throwing valid classes and custom markup in Chrome since Chrome supports the required attribute.