  The sensitivity of flow harmonics from cumulants on the event-by-event flow
distribution $p(v_n)$ is investigated using a simple central moment expansion
approach. For narrow distribution whose width is much smaller than the mean
$\sigma_n\ll < v_n >$, the difference between the first three higher-order
cumulant estimates $v_n\{4\}$, $v_n\{6\}$ and $v_n\{8\}$ are not very sensitive
to the shape of $p(v_n)$. For broad distribution $\sigma_n\gtrsim < v_n >$, the
higher-order cumulant estimates differ from each other but may change sign and
become ill-defined. This sign change arises from the choice of $p(v_n)$,
without the need to invoke non-flow effects. Direct extraction of $p(v_n)$ via
a data-driven unfolding method is a more preferred approach for flow
distribution measurement.
