Itís hard to tell from your picture what model of RV, what prop type, or where the cracks are.
Have you had a dynamic prop balance? It looks like in your picture that the bolt heads are in the aft side of the connection to the backplate bulkhead. Standard practice would have the bolt head on the forward side with a washer, since itís in fiberglass, but the manufacturers instructions may be different, due to interference issues, etc.
RV6/2001 built 2000/sold 2005
RV8 Fastback/2008 built/sold 2015
RV6/August 2022 build - Phase 1