[POWER RANGERS] Mighty Morphing Power Rangers what happened?

This may have been covered before in which case I am sorry but I am new, why was the original movie not in continuity with the show? Like how the rangers get there Ninja power, how the suits are completely different even the ranger weapons and made up helmit functions.

I remember watching the movie around season 2 back in the 90's and when season 3 started and they went on a quest to get ninja powers as a kid I was confused and actually a little angry.