Grade Forum UI Broken on Safari

macOS, Safari 13.0.4

When navigating to the "Grade Users" interface for a forum assignment in safari, the UI does not appear correctly: 

• The "Grading {assignment name} heading, grade input field, and Notifications radio buttons do not appear
• The navigation links cannot be clicked (it appears other content is layered on top of them so they are not receiving the click event)

The UI works correctly on Chrome. It appears the DOM is the same, so this seems like a styling issue.