The rail operator announced the postponement of the launch in September, just a day before its scheduled start, after spotting a glitch that could make trains go to wrong destinations.

An investigation panel chaired by a former Kowloon-Canton Railway Corp chief executive, Edmund Leung Kwong-ho, released its findings yesterday, concluding the glitch was a reliability issue instead of a safety one.

The issue was first noticed during a test conducted after hours in May, causing a train to head to the wrong station.

The problem was caused by a software module, unrelated to safety, being overloaded by a new module specifically designed to provide extra train monitoring info to the operations control center.

The contractor, Siemens, has resolved the issue by upgrading the software and stopping the new software module.

"The staff involved underestimated the technical complexity of the issue and were not sensitive enough to public expectations on service reliability," Leung said. Not informing the government was a misjudgment on the MTRC's part.

MTRC chief Jacob Kam Chak-pui said it has accepted the panel's recommendations.

"A dedicated Shatin to Central link technical and engineering assurance team, directly accountable to the CEO, has been established to monitor the project," Kam said.

A new signaling system, to match shorter nine-car trains instead of current 12-car ones, is part of preparations ahead of the launch. Shorter trains are necessary to fit the link's platforms.

Kam refused to say if the signal launch delay would affect the commissioning date of the link, set for the first quarter of 2022.

The government expressed "grave disappointment" that the incident led to the postponed launch of the new signaling system and the possible deferral of the commissioning of the cross-harbor section of the East Rail Line.

"It reserves the right to take further actions against the MTR Corp," a government spokesman said.

Meanwhile, an expert adviser team has submitted its final report with 42 recommendations for improving the rail link. It included a recommendation the Highways Department carry out further analysis on the structural integrity and long-term durability of slabs at Hung Hom station.