Telstra customers have been hit by another service issue, with delayed missed call and voicemail notifications suddenly appearing on phones despite some users saying their devices had never rung.

The telco confirmed on Wednesday night that an issue affecting its MessageBank service had caused multiple notifications to arrive at once.

Telstra said the underlying problem had been fixed and apologised for the confusion caused to customers.

According to the company, the MessageBank fault did not affect normal voice calls, mobile data or Triple Zero services.

The unexplained notifications initially prompted speculation among some customers that Telstra may have suffered a cyberattack or data breach before the company clarified the cause.

Reaction online was predictably less forgiving, with customers questioning Telstra’s service reliability amid rising telecommunications costs.

Photo by Jonas Leupe

The latest problem follows a major Telstra outage on July 8, which disrupted mobile services nationally and resulted in hundreds of unsuccessful Triple Zero calls.

That outage was ultimately traced to a GPS card that caused part of Telstra’s network timing infrastructure to reset its clock to 2006.

An audit released in September subsequently identified shortcomings in the way alarms associated with the network’s timing servers were monitored.

According to the findings, some alarms were checked only during business hours by a limited number of staff and were not visible through the monitoring systems used by Telstra’s round-the-clock support teams.

The report also found that two of the principal engineers involved in updating the network time protocol equipment were on mandatory stand-down at the time.

While the latest MessageBank incident was considerably less serious than the July outage, it adds another service disruption to Telstra’s recent record at a time when network reliability remains under increased scrutiny.

Featured photo by Stefan Stefancik