FaceTime audio "Answerd on other device"

[ytech]

Hey
I just experienced a very odd thing, I received a FaceTime audio call from a number that I'm not familiar with and apparently the call was "answered on other device".
I am familiar with all the devices that are signed in with my Apple ID, I have a very strong password and I use 2 step verification.
Can someone explain to me what is going on?

Thanks

 

[Freakonomics101]

I'm not exactly sure what happened and I really wish I had the answer. But I would change your password and secret questions on your account.