We have a client that is using SharePoint online to host a form library. This form library has a workflow attached that creates a task. The task form includes a SharePoint-generated link to the form. The link is formatted as http://[site]/[library]/[document name].xml.
When a user clicks on the link the InfoPath form opens in the same window. When a user clicks the submit button on the form the entire window displays a "processing" message but the window never closes.
If the user clicks the "close" button, the task form is displayed in the entire window. If you attempt to press any of the buttons nothing happens.