Take easy guys, after looking closely at the effect I´m sure that is a over scaling bug.
I did explain it in my last post but not sure if its not clear enough or this thread is becoming a denial niche like others did in past.
Anyway I had time to waste and do a graph of this bug and expose it clear, hope it informative
As we can see in this screenshots the effect is over-scaled to the point of show pixels :
The inner zone of the effect disc have a transparent zone that is showing aliasing (as we can see) due the over-scaling, probability that zone is what is left there for the blade joints so we can have idea of what point is reached by this over-scaling issue, and its huge
Here a graph showing more or less what are we seeing :
As is show in the graph what we are seeing is the over-scaled inner zone of the disc effect, the most dark one is over-sized to the point of reach the pit view, the clear zone is out of the draw zone assigned to draw the prop effect so we cant see it.
Im sure that this is what is happening here, watch it by your self, its a bug.
Having said that I share the idea that the propellers effect should be improved in his pit view and external view, there room to reach a more realistic representation, it should be visible under low rpm but barely in high and be affected by sun reflections and rpm range to the point of feel that we are controlling it with our hand, bringing us a better immersion.