This can have a big impact if you look at the list of top valuation gains and losses. A company with a recent stock split will shoot right to the top or bottom of the list.
This anomaly can also impact the valuation percentage as well for short periods of time as the valuation are based on earnings per share analyst projections.
I'm trying to think of a way to fix or at least flag this, but until I do, just note this as part of your due diligence.