"95% accurate" - there isn't such an optical viewfinder. IOW there isn't an optical viewfinder which will give you guaranteed the final result with at least 95% accuracy.
Most probably you mean 95% coverage - this means that you see through your viewfinder only 95% from your photo area. So, it is nothing related to the bokeh.
Speaking simply, as we all (should) know, the bokeh is related to the lens aperture. What do you see through the OVF is the scene at the maximum lens aperture which is used by the camera to do its metering, AF etc.
If the difference between the lens's maximum aperture (say, f/2.8 or f/1.8) and the actual aperture at which the photo was taken (for ex. f/11, 16 or even 22) is big then the difference in bokeh is obvious. To test this you can use the DOF button if your camera has it.
Another thing to consider is the nature of our eye. The eye 'sees' a very small part of the image. When you want to see the 'blurred' part, then your eye 'refocuses' automatically there and the 'blurred' part becomes clear. In fact, in the day-by-day life you cannot see the 'bokeh' (or very hardly see it) because the human eye cannot see 'unfocused'. It focuses instantly at the point where the eye ...focuses (IOW at the point where the eye looks at).