Greg, it is more to do with how it reads. It would be exppected to be more common at higher altitudes/lower pressures as trapped gas expands more as the pressure decreases. The questions are not unprofessional but they do require a level of comprehension that is different to everyday speech. Think about it, as soon as pressure decreases gases expand. Not much non-pressurized flight for passengers these days but the cabin pressure is also kept around 7,000 ft in transport jets. Do not worry too much, greater exposure to questions compiled from all over Europe and not all written by people with English as their first language may have a part to play too. Try and be logical when disecting questions. You will learn a lot, and quickly, keep going but make time for some rest and relaxation too.