Wouldn’t this be the second time since Mubarak’s departure?
Yes, it's happened twice since his departure but three times this year.
A quick search showed it happened Feb 5th and he stepped down a week later. That attack led to a 38-day supply gap.
It happened again in late April causing a 45-day supply gap and now, a third time this year only 24 days after resuming supply.
I found a Jun 3rd piece reporting Egypt's oil minister said no gas exports to Israel and Arab countries until the pipeline was secured and supply started up again the 10th.