It's not like Power Rangers
has ever had a tight continuity. Lost Galaxy
was supposed to be several years in the future, long enough for Earth to have invented interstellar drives, but then later seasons treated it as if it had taken place the same year it aired. Alternate or no, RPM
was clearly presented as being sometime in the future. As far as I know, there was nothing in "Clash of the Red Rangers" that precluded the two from being in different times as well as different timelines -- especially since there was zero explanation given for how the universe transfer even worked.