I’ve noticed that someone keeps searching variations of that question on the search bar, and I’d like to finally answer your question. They can’t desync the way that a human would. They will sometimes get out of synchronization by accident, but there’s nothing advantageous that can be taught from it. We can’t even teach them to desync on their own!
Amiibo AI is oddly finicky in many, many ways, and it’s often character-specific. Ganondorf, for example, uses up-tilt and only up-tilt given enough time. You’re not training him wrong, he’s just poorly programmed. Sheik will never escort someone all the way to the blastzone with her forward air, even when she could easily recover with it. There’s an invisible line where she’ll stop edgeguarding and return to the ledge. Ken can’t even use his character-specific inputs, but Ryu can!
If you have questions about your favorite character or amiibo, you can always ask them at the Amiibo Dojo.