NestedElements were not assembled (InitialAssembly)
After 2e00f41b NestedElements are no more derived from DofOwnerOnwer. For this reason they need to be special-cased whenever one tries to undertsand whether the underlying element is a DofOwnerOwner. This is accomplished by a dynamic_cast of the generic element pointer into a NestedElement*, then extracting the underlying wrapped element pointer and performng the DofOwnerOwner check onto that last one.