Spinner Doubler Cracks

My CS spinner backplate doubler ring is cracked. Noticed just as we were about to install. Interesting thing is, the prop had a ring and reseal done when it wasn't brought to my attention.

Have ran into cracks in the ring similar to yours.
Have also ran into cracks in bulkhead but the ring was ok.
Have found the odd rivet head missing, ring & bulkhead ok.
Only once I found crack through both but that spinner definitely showed signs of being over torqued.
I know the cause of the last one, would be curious what caused the other 3.