Windows 10 and Radeon HD 5450
To view bug-
Turn on surface deform modifier on Eyebrows- Surface and Eye Lashes- Surface. Toggle Vyrath Surface's armature on and off repeatedly.
View again with surface deform active only on Eyebrows- Surface.
These surface deform modifiers should not interact with each-other in any way. However, when all surface deform modifiers are active, the result is different from the individual results when only one surface deform modifier is active.