Cache update after mutation with writeFragment

client.tsx

            createCaseFromEvent(result, variables, cache) {
              const readEvent = () =>
                cache.readFragment(
                  gql`
                    fragment _ on CaseManagementEvent {
                      id
                      cases {
                        id
                        status
                      }
                    }
                  `,
                  {
                    id: variables.eventId
                  }
                );

              console.log(readEvent());
              cache.writeFragment(
                gql`
                  fragment _ on CaseManagementEvent {
                    id
                  }
                `,
                {
                  id: variables.eventId,
                  cases: [result.createCaseFromEvent as CaseManagementEventCase]
                },
                {
                  id: variables.eventId
                }
              );
              console.log(readEvent());
            }