The final games after the ranking period for the big programs have always been rest/suspension/bottom-6-liners games. Think of it like a preseason game. The only reason they're on the schedule is to clear any game misconducts / suspensions for the upcoming tournaments. So CSU losing in that game against Wyoming doesn't surprise me, nor should it be considered important to rankings as the system stands now.
It's a quick fix if they want to prevent this tactic, extend the ranking period out to include the mid-Feb weekends and make it so any games played after the final rankings do not count for serving suspensions.