Line artifacts are observed with realtime directional shadows. The issue is noticed with devices that has Adreno GPU.

Steps for reproduction:
1) Download the project attached to the case and open the scene `level`
2) Switch the build target to Android and deploy to a device with Adreno GPU
3) Observe the bug

Notes:
- Regression introduced in 5.6.0b2
- Reproduced with 5.6.0b11, 5.6.0b10, 5.6.0b5, 5.6.0b2
- Not reproducible with 5.6.0a3, 5.6.0b1 and 5.5.x

Devices where the issue is observed:
HTC 10, OS: 6.0.1, GPU:Adreno (TM) 530
Xiaomi MI 5, OS:6.0.1, GPU:Adreno (TM) 530
Xiaomi MI 5s, OS:6.0.1, GPU:Adreno (TM) 530
Xiaomi Mi 4i, OS:5.0.2, GPU:Adreno (TM) 405
Xiaomi Redmi Note 3, OS:5.1.1, GPU:Adreno (TM) 510