Reproduction steps:
1) Open "806929_ReproProj.zip" project
2) Open "BugScene" scene and notice UI elements in Game View
3) Enter playmode and rotate camera using Alt button and moving mouse
4) Notice how UI renders while moving mouse
5) Set the GVRViewerMain's Distorsion Correction to None, notice how it works as expected

Expected result:
UI should be steady

Actual result:
UI juddering while moving mouse (rotating camera)

Note:
Issue does not persist on device.

Regression from:
Flicker began with 5.4.0b24

Problems with UI began with version 5.4.0b18