Why is the Unshare and Update Template not displaying?

Like others have already commented - the sharing dialogue does not offer the UNSHARE or UPDATE options so the form remains available as before.

I have tried sharing a test form to the Form Templates and able to share it normally. When you click on Share as Template option for the same form, the pop-up for the template shall be displaying the options Unshare and Update the form.

Please give it a try and let us know if you need any further assistance. We will be happy to help.