Desertion of the Dinobots (1) - S2-E19
Plot hole: Perceptor discovers that the reason for their malfunctioning is because their Cybertonium has deteriorated after millions of years of being exposed to Earth's atmosphere. The key word here being 'millions'. This explains why the original Transformers who crash landed on Earth (4 million years ago) are affected, but newer characters like Perceptor, Powerglide, Hoist, etc. are affected despite the fact that they have only been on Earth recently.
Plot hole: Omega Supreme transforms his arm into a rocket and blasts off to the moon, but later, he transforms fully, but he left his body on earth, how was he able to transform?
Answer: These two were 'dinosaur' cassettes Overkill and Slugfest, then-new toys. They turn up this once and that's it, though.
Daria Sigma