Less-so that it has expanded from the decaf process, and more-so that the additional porosity leads to the 'crack' you get from reaching that critical temperature is much less violent, since there's essentially already many micro-fractures in the bean. Think of it like attempting to burst a pipe with a leak in it, vs. a pipe that is sealed. The leak will bleed off pressure, so you need much more flow (in coffee roasting, this would be power from heat) to get the same build up and explosion.