Shadow artifacts will appears when the camera is moving towards a character or if playing will appears with the character if Self Shadow is enabled for the character.
Sample video and image attached.
1. Open Third Person Template
2. Select the Player Character in the map
3. Set Self Shadow Only to TRUE
4. Move the camera around the player and/or PIE
Results: Shadow artifacts of using self shadow only enabled.
Expected: shadow artifacts should not be present.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-20810 in the post.