  Measurement of spin-precession in black hole binary mergers observed with
gravitational waves is an exciting milestone as it relates to both general
relativistic dynamics and astrophysical binary formation scenarios. In this
study, we revisit the evidence for spin-precession in GW200129 and localize its
origin to data in LIGO Livingston in the 20--50\,Hz frequency range where the
signal amplitude is lower than expected from a non-precessing binary given all
the other data. These data are subject to known data quality issues as a glitch
was subtracted from the detector's strain data. The lack of evidence for
spin-precession in LIGO Hanford leads to a noticeable inconsistency between the
inferred binary mass ratio and precessing spin in the two LIGO detectors,
something not expected from solely different Gaussian noise realizations. We
revisit the LIGO Livingston glitch mitigation and show that the difference
between a spin-precessing and a non-precessing interpretation for GW200129 is
smaller than the statistical and systematic uncertainty of the glitch
subtraction, finding that the support for spin-precession depends sensitively
on the glitch modeling. We also investigate the signal-to-noise ratio $\sim7$
trigger in the less sensitive Virgo detector. Though not influencing the
spin-precession studies, the Virgo trigger is grossly inconsistent with the
ones in LIGO Hanford and LIGO Livingston as it points to a much heavier system.
We interpret the Virgo data in the context of further data quality issues.
While our results do not disprove the presence of spin-precession in GW200129,
we argue that any such inference is contingent upon the statistical and
systematic uncertainty of the glitch mitigation. Our study highlights the role
of data quality investigations when inferring subtle effects such as
spin-precession for short signals such as the ones produced by high-mass
systems.
