Flickering shadows from directional light at certain camera angles

I've been struggling with this issue for some time now: my shadows start to flicker and disappear as soon as I angle the camera away from straight along the Z-axis. This is very annoying as the cockpit shadows flicker enough to give you a headache. All other long-distance shadows appear fine, i.e. the shadows the ships cast on other objects never seem to flicker.

I have tried reducing the far clipping planes, increasing the near clipping planes, maximizing shadow quality settings, switching...

Flickering shadows from directional light at certain camera angles