The robot body of "Mecha-Hermes" takes on the voice and mind of Roberto, the insane criminal robot, before Roberto's "Brain Circuit" is installed. In fact, the brainless robot puts the ciricuit board into his own head on his own. (This was probably an intentional recursive joke.)
When Hermes stepped on Fry and Bender's airhoses, it should of been just Fry's because Bender doesn't breathe.
When Zoidberg puts Hermes back together, the mark where his brain was removed is shown to be stitched but Zoidberg didn't stitch Hermes brain back in.