It said the report issued by Leighton Asia was aimed at exonerating them of any responsibility.
The commission’s chairman, Michael Hartmann, said any threat in relation to procedural unfairness should be taken seriously. He said he would allow time for relevant parties to study the matter.
A general manager of Leighton was supposed to give evidence on Monday. That has been rescheduled for a later date.
The hearing will resume on Tuesday.
The commission was set up after reports of reinforcement bars being fitted into a platform slab were deliberately cut short, sparking fears that the project was unsafe. It was also revealed later that workers had trimmed the diaphragm wall without informing the authorities.
But its term was extended after the panel was asked to look into reports that contractors had failed to hand in key records when building the station’s approach tunnels and secondary tracks.