  Recent studies have revealed that the onset age for the presence of multiple
stellar populations (MPs) in star clusters seems to correspond to the
disappearance of the extended main-sequence turnoff (eMSTO) in young clusters,
a pattern associated with stellar rotations. A speculative suggestion is that
MPs might be caused by the magnetic brake, a stellar evolutionary effect linked
to the rotation. In this work, we use the young massive cluster NGC 419 as a
testbed. We examined if its magnetically baked MS stars would exhibit MPs.
Using the deep ultraviolet and visible images observed through the Hubble Space
Telescope, combined with a specific color index that is sensitive to the
nitrogen (N) abundance, we examined if its late G- and K-type MS stars are
affected by N variation. Our analysis reports that the morphology of its
GK-type MS is most likely an SSP, and only a negligible probability that
indicates a N variation up to 0.4 dex is present. We conclude that there is no
significant N variation among its GK-type MS stars. The absence of a
significant chemical variation among the late-type MS stars indicates that MPs
might not be a specific pattern of magnetically braked stars.
