When we load the diff viewer, we include the latest activity timestamp in the page data. This is then used with subsequent accesses to the last-update resource to determine whether to show the updates bubble. The timestamp of a draft diffset was being included in the initial activity timestamp, while it is not included in the timestamp returned by the API. This meant that the updates bubble would pop up saying the diff was new because the timestamp did not match. Testing Done: Loaded the diff viewer with a draft diff (while viewing as an admin user). Saw that the updates bubble no longer popped up incorrectly.