There is a set of tiles with SSE above "errorThreshold" that never gets loaded (or gets unloaded) when the camera is zoomed far into the terrain. When zooming back out though those tiles start to meet the screen space error requirements causing it to jump back to a coarse level of detail.

Current Behavior

If a tile meets the SSE requirement load and render it. Once loaded load and render all children. Only render children if they're all ready.

New Behavior

If a tile meets the SSE requirement load and render it if a child tile was not rendered the previous frame. If a child was rendered previously or if this tile is loaded then load and render all children. Only render children if they're all ready.