I dobt they had any issues prior to the insident. First of all, another a/c came right behind, second that runway would not be chosen, as it is only 7001 feet. That length isnt even enough for the larger variants of the 737 series for normal operations, so it would be marginal for this 737-700. With any indications of landing gear problems, they would chose a much longer runway somewhere.
Possibly a structual issue and/or a hard hit for the nose wheel (by nose wheel landing or hard drop to the runway after touch down). The wheel must have been down and locked, as red lights and GPWS would have gone off if selecting landing flaps with not all three gears down and locked.