JP Choro Q "metallic" Rodimus (and probably the others as well) suffers from Brittle Plastic Syndrome.
Fresh out of a sealed box, I turn the yellow back fin, and the little knob that locks into a tiny dimple at the front and back (for the two modes)
knocks out a chunk of plastic where the dimple was. There is now a hole in the back panel that is about the size of half a pea.
The arms were really stiff, and creaking, so I stopped transforming it halfway and put it back in Robot mode.

The plastic is very sparkly, and not flexible like regular Transformers toy plastics. Any attempt at bending a plastic panel was met with creaking and stress marks.
The black "metallic" Megatron I got had the same creaking sounds, so I had to be really careful transforming it (I didn't get the "TV" version, and wanted to see the gun mode).

I'll take some photos later, to replace this one, which just shows people which toys I'm talking about (the four little ones in the middle).