There is currently a bug that occurs for some instructors where a quiz doesn't show up in the LockDown Browser dashboard.
The bug is caused to a "null" field being reported to the Respondus LockDown Browser dashboard.
To resolve the issue, instructors should edit the quiz within D2L Brightspace, go to the Submission Views tab, click on "Default View", click in the "Message" box, and press the space bar. Once that is done, click Save until you are back to the Quizzes tool. Your quiz should now appear when you click on the LockDown Browser dashboard tab in Quizzes.