Thanks for the responses, everyone.
What the others posted above is spot-on for the reasoning. There's just 1 thing that I'd add in defense of WrestleStat's ELO rating system used for the rankings:
If you check the individual pages for the two wrestlers, Griffith moved up almost 4 ELO points, desipite dropping 1 position in rankings, while Shields moved down 3.5 ELO points, despite staying ranked the same.
Those two guys were fairly close prior to this weeks rankings (roughly 9 ELO points apart), and now after the 7.5 point ELO change between the two, they are now only 1.5 ELO points apart. That's close enough where, if Griffith majors his next opponent, while Shields only gets a regular DEC, that will probably be enough for them to flip-flop in rankings.
(Check the rank history tab on each of their profiles)