Office Excel macro:Error rendering macro 'viewxls' : Unrecognized date string, please use mm/dd/yyyy

Regression of CONFSERVER-32468.
Replicated on 6.12.2 and 6.14.1

We have an attachment called Business Objectives.xls, (attached), and when we try to display the content of the file using the Excel macro in a page titled (3/5/14-4/29/15), it fails to render and instead throws the error below, (see the attached screenshot XLS_bug.jpg):

Error rendering macro 'viewxls' : Unrecognized date string, please use mm/dd/yyyy

Notice how the macro appears to be picking up the wrong page name, (see previously mentioned screenshot "XLS_bug.jpg"), when on the page titled (3/5/14-4/29/15) it becomes truncated to /5/14-4/29/15).

Embedding the same spreadsheet in a page with the title Test XLS, (or any other title which doesn't contain date like formatting), allows the content of the spreadsheet to be rendered normally, (see attached screenshot "Working_example.jpg"), and the naming convention of the file also appears to have no impact on the bug.

This issue is specific to pages which contain date-like formatting in their titles, for example the page title (3/5/14-4/29/15).