A three.js light's shadow camera ignores the bounds you assign until updateProjectionMatrix is called

Fact

DirectionalLightShadow is constructed with an OrthographicCamera(-5, 5, 5, -5, 0.5, 500). Assigning light.shadow.camera.left/right/top/bottom/near/far changes those properties and nothing else: LightShadow.updateMatrices() runs every frame and rebuilds the camera's view matrix from the light's position, but never its projection matrix.

So a shadow volume "widened" to cover a scene silently stays 10x10 units.

The second half is what makes it destructive. shadow.normalBias is measured in world units and is normally sized against the texel size of the box you intended (2 * extent / mapSize). Against the 10x10 box that is actually in force, that same value is hundreds of texels, so every lookup samples far outside the map and large regions come back shadowed.

Why it matters

The symptom is not "shadows are the wrong size" — it is broad, hard-edged dark patches across geometry nowhere near the caster, which reads as a lighting or material bug. The shadow configuration is right there in the source looking correct, and every value in it is the value you set.

It also survives a code review, because the fix is a call that is not in the code rather than a wrong value that is.

How to apply

• Call it yourself, immediately after setting the bounds:

  Object.assign(light.shadow.camera, { left: -e, right: e, top: e, bottom: -e });
  light.shadow.camera.updateProjectionMatrix();

• Size the biases against the box that is really in force: const texel = 2 * extent / light.shadow.mapSize.width, then normalBias ≈ 2 * texel.
• Any camera whose left/right/top/bottom/near/far are changed after construction needs the same call; three only rebuilds projections for the cameras it owns end to end.