User does not change anything in Client Play Camera Shake.
Reproduced in 4.8 and Main (//depot/UE4/Promotable-CL-2581498).
This is a Regression: it works as expected in 4.7.6
1. Create a new Third Person template project
2. Create a new Camera Shake Blueprint
3. Set the Oscillation Duration to 1.0
4. Set the Rot Oscillation Pitch Amplitude to 5.0
5. Set the Rot Oscillation Pitch Frequency to 50.0
6. Open the ThirdPersonCharacter BP
7. Add an input key event
8. Get Player Controller > Client Play Camera Shake
9. Set the Shake Class to the Camera Shake BP created in step 2
10. Set the Scale to 1.0
11. Set the Play Space to User Defined
13. Press the input key
14. End PIE
15. Set the User Play Space Rot to R=90, P=90, Y=90
17. Press the input key
Adjusting the value of the User Play Space Rot makes no difference to the Camera Shake.
In 4.7.6, there's a visible difference in the camera location during the shake.
Head over to the existingAnswerHub thread and let us know what's up.