Telstra Group (ASX:TLS) released the findings of an external expert investigation into its July mobile network outage, confirming the company's previous conclusion that the incident was triggered by a technical issue, according to a Wednesday filing with the Australian bourse.
The investigation by Technology Audit Partners (TAP) found that incorrect date information was transmitted through parts of the company's mobile network after planned maintenance on the network timing system.
"Most significantly, TAP found the outage was primarily a result of us not treating network timing as a critical capability within the network (or a 'sovereign function') requiring the highest levels of oversight and protection," Telstra said.
Among other shortcomings in process discipline, the investigation found that responsibility for the function was not sufficiently defined, the company had insufficient technical expertise for network timing systems, and the architecture supporting network timing evolved over time without adequate end-to-end oversight.
While gaps in ownership and operational support delayed the identification of the problem in the early stages of the outage, Telstra effectively managed the recovery after initiating a major incident response, the probe found.
"We accept the findings of TAP's investigation," Telstra said, reiterating that the outage "should not have happened." Remedial actions are not expected to have any impact on fiscal 2027 guidance, the company added.