Katherine fails to make an interpersonal mess

Here's a brief description of the contestant's attempt. Someone's probably working writing up more detail!

Katherine decided to ring her sister and tell her that her brother-in-law had been cheating on her, to which her sister claimed she had been cheating on him anyway. She then rang her Dad to tell him that her sister was pregnant with another man's child, which he didn't believe. Katherine then called her sister back to say that it wasn't actually Alan she saw, so he wasn't cheating, but her sister replied that she had already told Alan that she had been cheating on him. Katherine then tried to ring Alan to let him know her sister was joking, but ended up telling his friend Abe instead.

(Written by Taskmaster Wiki contributors)