In "Monstory" when the citizens flee after seeing the giant "telescope" (later revealed to be a microscope used by Dexter to watch sub-molecular lifeforms) and before Dee Dee enters Dexter's room, a camera cuts to Dexter's left ear showing he is using a sound amplifier to hear what the sub-molecular lifeforms are saying, however in immediate subsequent cuts (such as when the pin drops, when Dee Dee says "Hiiii!!" or when he takes it out of his ear) the sound amplifier is in his right ear.
In "Inflata Dee Dee", when Dexter uses the "chopper colored cap" but accidentally gets it stuck between the two lasers, after the mechanism twists Dexter, the cap just uncouples from Dexter causing him to fall. If the invention would have had this limitation, then he wouldn't have been able to get of the ground in the first place. It is also not possible for the cap to have been uncoupled, since several shots show it's hooked to the harness on Dexter's back and to the control sticks.