[Grammar] her phone switched off or having been switched off

[lagoo]

Here is the sentence : "When Brjánsdóttir didn't show up at work on Saturday, her phone switched off, Hreinsdottir knew something was wrong.."


I think the clause "her phone switched off" is grammatically wrong.
It should be " her phone having been switched off".
Am I right?

 

[emsr2d2]

Even that doesn't lead to a particularly good sentence. I'd say "When XX didn't show up at/for work on Saturday, and her phone was off/and she wasn't answering her phone, ..."