Incorrect number of nodes in queue after reordering/removing

I'm seeing that the number of nodes in a queue is incorrect on the /admin/content/nodequeue page after certain reordering operations. For example if I start with 7 nodes in a queue:

1. A node is added to the queue using the "add to nodequeue name" link on the view of the node. The number of nodes in the queue is now correctly reported as "8"
2. The "View" link for that node is opened in a separate browser tab. The node just added is visible at the bottom of the list as expected.
3. The "Move to front" button is clicked for the newly added node.
4. The "Move down" button is clicked for the newly added node.
5. The Save button is pressed.
6. On the /admin/content/nodequeue page, the number of nodes in the queue is now reported as "14" (should be "8"). See screenshot of nodequeue_nodes table at this point.
7. The "Remove from queue" button is clicked for the newly added node (currently in 2nd position).
8. The "Save" button is pressed.
9. On the /admin/content/nodequeue page, the number of nodes in the queue is now reported as "10" (should be "7"). See another screenshot of nodequeue_nodes table at this point.