Can condensation cause laminate flooring to swell?

Most laminate floors have either a polypaper or polythene membrane underlay, some floors have felt slab underlay. If yours has felt underlay its entirely feasible that the felt has absorbed water from the concrete floor slab, this could have become saturated and the lam floor absorbed moisture from the felt. You mentioned swelling, is this around the edges of the planks? ie. where they join together? if so then its almost certainly moisture ingress. If you have a polypaper membrane the likelyhood of it being the floor is reduced a bit, however, moisture can wick through the paper overlaps.