Indeed there is an error in the original code. Your change is correct adding this line there. Thanks for that.
With that said, I’ve just tested this with the UnityChan model on the asset store as an example and the SetBool now works correctly when scrubbing the time in editor. I’ve tested with Slate 1.2.5 and Unity 5.3.4f1.
Are you on 5.3.2f1 as stated or did you also mean 5.3.4f1?