A depth violation is when an object is positioned in 3D space in front of another object, but is rendered as if it is behind it. It can be uncomfortable to look at.
The most common occurrence happens when UI is rendered on top of 3D scenery.
Moving UI elements off to the side and away from objects will remove the depth violation.
Some depth violations are unavoidable. They can be improved with strategic UI placement. On the left the UI element will have depth violations on 3 sides. On the right, there will only be one depth violation.