  Recently CMS Collaboration measured mixed-harmonic four-particle azimuthal
correlations, known as symmetric cumulants SC(n,m), in pp and pPb collisions,
and interpreted the non-zero SC(n,m) as evidence for long-range collectivity in
these small collision systems. Using the PYTHIA and HIJING models which do not
have genuine long-range collectivity, we show that the CMS results, obtained
with standard cumulant method, could be dominated by non-flow effects
associated with jet and dijets, especially in $pp$ collisions. We show that the
non-flow effects are largely suppressed using the recently proposed subevent
cumulant methods by requiring azimuthal correlation between two or more
pseudorapidity ranges. We argue that the reanalysis of SC(n,m) using the
subevent method in experiments is necessary before they can used to provide
further evidences for a long-range multi-particle collectivity and constraints
on theoretical models in small collision systems.
