Uploading a file to an activity with multiple custom file fields removes the existing attached files

As noted in https://issues.civicrm.org/jira/browse/CRM-8936
It appears that although a patch was provided in that issue it may not have been adopted in the core.
I've just come across the same problem on a live site running version 4.4.6.
we are shortly to update to 4.5.x so it may have been addressed elsewhere, but thought I'd log this now just in case.
I'll update with any details post upgrade, but for now this is a major issue on the site I'm working on.