When Billy is supposed to dislocate a bomb that Howard has hooked to him, the camera gets a closeup on the ticking bomb from 19 seconds down to 16 before going to the next shot of Billy talking to Howard. In the next shot, another closeup of the ticking bomb shows the timer has gone back at 19 seconds as it counts down.
Zordon claims Rita wants to use the "invisibility" formula to make the Power Rangers disappear forever. This makes no sense at all. All the formula does is makes someone invisible, and only temporarily, as demonstrated by Uncle Howard at the end scene. It would make more sense if Rita was trying to get the formula to make her monsters invisible.