  We present a recent evaluation and updates applied to the Multi-Object
Spectrometer For Infra-Red Exploration (MOSFIRE) on the Keck I telescope. Over
the course of significantly long integrations, when MOSFIRE sits on one mask
for $>$4 hours, a slight drift in mask stars has been measured. While this does
not affect all science-cases done with MOSFIRE, the drift can smear out signal
for observers whose science objective depends upon lengthy integrations. This
effect was determined to be the possible result of three factors: the internal
flexure compensation system (FCS), the guider camera flexure system, and/or the
differential atmospheric refraction (DAR) corrections. In this work, we will
summarize the three systems and walk through the current testing done to narrow
down the possible culprit of this drift and highlight future testing to be
done.
