The Master Builders

Scrapper claims that the Constructicons have admired Grapple's work back on Cybertron millions of years ago. Yet formerly, in another episode, Megatron said the Constructicons were built recently on Earth. The rest of the cartoon also neglected this fact, and handled the Constructicons as if they were millions of years old. There is the possibility the Constructicons were aboard Megatron's Cruiser, just not functional and building them may have been a reference to activating/assembling them as other stories have featured them in Cybertron's past.