  The Galactic bulge source MOA-2010-BLG-523S exhibited short-term deviations
from a standard microlensing lightcurve near the peak of an Amax ~ 265
high-magnification microlensing event. The deviations originally seemed
consistent with expectations for a planetary companion to the principal lens.
We combine long-term photometric monitoring with a previously published
high-resolution spectrum taken near peak to demonstrate that this is an RS CVn
variable, so that planetary microlensing is not required to explain the
lightcurve deviations. This is the first spectroscopically confirmed RS CVn
star discovered in the Galactic bulge.
