  Hydrodynamics can describe majority of the measured azimuthal anisotropies in
relativistic heavy-ion collisions. Many of the anisotropy measurements are
contaminated by nonflow correlations (i.e., those unrelated to global
event-wise correlations). Those nonflow contamination can cause incorrectness
or compromise the accuracy of the physics extracted from data-hydrodynamics
comparison, particularly when one relies on subtle difference in the
measurements. In the recent preprint by STAR (arXiv:2401.06625) extracting the
Uranium nucleus deformation parameter, nonflow contamination is assessed by
subevents in the limited STAR acceptance. In this note, we demonstrate that
such assessment is inadequate and illustrate how large an effect nonflow can
cause by using the HIJING model, in which all correlations are nonflow and
non-hydrodynamic. We thereby conclude that the extracted Uranium deformation
parameter is premature and emphasize the importance of an earnest assessment of
or correction for nonflow contamination, not only for this STAR analysis but
more generally for studies relying on comparing anisotropy measurements to
hydrodynamic calculations.
