Yes, but that tended to happen in linear fashion. Whereas, after agriculture, growth could occur exponentially and then when a major multi-year drought would hit, you'd have huge devastating loss of life. The deaths of some H-G humans is not much different than the limits of growth modern predators hit today. Hunter-gatherer humans could also keep their numbers in check by breastfeeding longer (sometimes until their children were as old as 5), since breastfeeding delays ovulation. Agricultural societies, meanwhile, developed lactose tolerance for cow's milk, and could use that as a supplement for child nutrition. And women would spend more of their time on the work necessary to run a farm or home, which is more labor intensive than what nomadic H-G tribes did.

> doesn't "numbers were kept in check" mean "surplus people starved

Not so obviously. Would you argue this for (say) lions or eagles? Few adults starve, when times are lean there is less breeding, and fewer kids who survive, compared to times of plenty.

Whereas the collapse of an early agricultural society (perhaps due to pests, or just no rain) probably did result in lots of adults starving, if there were more of them than could be supported on gathered food.