Eagle-eyed fans noticed the character was holding her Nokia Lumia all wrong as she chatted to police about her recent break-in.
Viewers spotted that Ruby – who was on the phone to the police – was actually speaking into the headphone jack and not the mic.
One joked: "#EastEnders I swear ruby was just on the phone which was upside down lol ."
Another mocked: "Am I the only one who noticed Ruby was holding her phone upside down whilst talking on it? #eastenders @bbceastenders
A further teased: "@bbceastenders did anyone else notice Ruby’s phone upside down whilst making a call great phone call. #Eastenders
The blunder appeared to distract from the scene's serious subject matter as Ruby – played by Louisa Lytton – was actually arguing with police over rapist Matt Clarkson's involvement in the break-in of her home.
Still recovering from her horrific rape ordeal, the character was left shaken up once again this week when her flat was burgled.
But it seems police have reason to believe Matt wasn't the burglar after all – much to Ruby's dismay.
Despite her insistence that Matt is lying, it seems her protesting falls on deaf ears.
And things only go from bad to worse when her hotheadedness almost ruins her blossoming relationship with Jay next week.