Creating milestones using a custom action.

Ok.  I have a weird one.  I want to create a milestone using a template under a project that has all of its other milestones completed.  If I do this using the "Add" button, everything works as expected. However, I have a custom action that adds the milestone (after asking the user for several key pieces of information that we want to capture).  I use the same template in the custom action and it appears that everything is fine.  A few seconds after the milestone is created, though, it and all of the tasks that were created (from the template) are marked as 100% complete (even though they are not due for several days, and nothing has been done to them, not even a resource assignment).  I have disabled ALL workflows in our sandbox environment to try to run this down.  I have manually recreated the custom action, I have recreated the template and still no luck.  I have no idea how/why the tasks are marked as complete.