When logging in to Facebook/Yahoo mail, I receive my 2FA codes from random numbers. Here are some examples (I have a Romanian phone number, hence the country codes):
+40 747 691 103 +40 727 347 814 +40 758 942 742 +40 759 158 056
and the list goes on. It's a different number every time.
Furthermore, the text in the messages that I receive is grammatically all over the place. Looks like a legit spam SMS. However, the codes inside do work! I find this immensely odd.
Considering potential malware somewhere, I tried formatting my drive and reinstalling the OS. I also did a factory reset on my smartphone and the result is still the same. I even got a new SIM card and a new phone.
What I would expect is not to see a particular phone number, but only "Facebook" or "Yahoo" as the sender of the SMS. Could there be a man-in-the-middle?