Positive-Z view of world disappears from view, showing only sky at side of screen.

When turning from negative z (east) towards either positive x (north)or negative x (south), the blocks in the world don't show revealing the sky box, then suddenly pop in to view.

My normal play is at normal FOV. Changing to Quake Pro view helps to confirm that the blocks that the world thinks are behind me (towards the west) aren't being drawn until my view direction flips from east to north or south.

I've attached some screenshots with debug info, to help show that the effect occurs from bottom to top, and occurs on both the left and right of where I was standing.