Forever Red - S1-E34
Plot hole: Tommy states that he and the other Zeo Rangers destroyed the Machine Empire's leaders and ultimately destroyed the Machine Empire except for the Generals who escaped. This is not true - Lord Zedd and Rita destroyed the Machine Empire leaders at the end of series 4, and the Space Rangers destroyed them again in Countdown to Destruction in series 6. The Zeo Rangers never destroyed the Machine Empire.
Suggested correction: How would Tommy know that? He didn't watch the show or know the ins and outs of what happened in space. This is what he believed based on his experiences on Earth. Everything you described is factually correct, but Tommy did not witness this. So, to his knowledge, he destroyed the Machine Empire.
Plot hole: In Cam's song in the dream, one of the lines is: "No fun, no sun." However, at the start of the dream, all of the Dumping Ground kids are outside in the daylight.
Normal Boy/Birth of a Salesman - S1-E3
Plot hole: Throughout the show, many characters state that Jimmy was responsible for the meteor almost destroying Retroville in the episode "Normal Boy", however, how would anyone even know that? The meteor was put on course after being hit by some kitchen objects shot into space by Jimmy's orange juice machine. Neither Jimmy nor his parents or anyone saw the objects go into space, much less witness them causing the meteor head straight to earth, especially since the meteor wasn't detected until the next day.
A Scooby-Doo Valentine - S3-E3
Plot hole: It's never explained how JC Chasez and the Hollywood extras impersonating the gang gained the super strength they possessed to do things like ripping car roofs open or holding up the Mystery Machine.