8.0.0-RC1 breaks ZkToDo2 demo with ZK error "cannot create proxy java.sql.Timestamp empty constructor needed"

upgrading the ZkToDo2 demo project at https://github.com/simbo1905/ZkToDo2/ to ZK 8.0.0-RC breaks clicking on saved data which contains a date with the error shown in the attached screesnshot. "Cannot create a proxy object:[class java.sql.Timestamp], an empty constructor is needed".