Sounds like a pinch flat to me. My suggestions are:

-If you want same comfort and add durability, go up a tire size. More volume but at a similar pressure in the bigger tire you likely won't pinch flat as much. Otherwise, you'll just have to add pressure to avoid the pinch flats.

-Comort, speed, and durability.......that bike's specs online say it is a 700c. They DO sell latex tubes for cyclocross bikes that are 700c. I think they should work in a tire from 32 to 40ish in size. Latex is slightly less prone to pinch flats. If worried about thorns, just buy a type with the removable valve core and pour in some sealant to the tube. It's a utility bike, not a racer, but latex can still provide added comfort and durability despite its fragile reputation.