Ring Central support confirmed for me that this was a change. There solution was to go thorugh one by one on our users and download the voicemail from their primary setting, and upload to their DND.:

Here was my response.

While I appreciate your response, it will not solve our problem. Most of our staff record a custom greeting, and frequently are changing it to make it personal and timely. Your suggestion of downloading and uploading the custom greeting to make them unified would need to be done EVERY DAY to make this work.

When did this change take place, and how was it communicated to your clients? When you make a change to your interface that breaks existing behavior and requires user intervention to address it, those type of changes needs to be overly and directly communicated. based on what you have described, the only solution available to us is to double the work required to setup the voicemail of our staff, without having any clear instructions that we can provide our staff with as to how to do this themselves. Please try searching RingCentral support for "How do I change the voicemail for Do not Disturb". If you get results like me, there is no content out there even referencing that this "Feature" exists

As I understand what you have described to me, RingCentral made a change that broke functionality, and rather than rolling it back, clients are supposed to just know this change happened without announcements or support documentation.

What RingCentral needs to do, in my opinion, is one of 3 things
1) Add an option to the DND Dropdown that chooses "Primary Voicemail Message" and make that the default.
2) Provide a system wide option for the admin to choose if DND voicemail messages are unique or not
3) Roll Back the change.

As far as I recall, This used to be unified. This appears to be a bug, not a feature change. RC staff, please comment