I sent a text to a friend who I have texted in the past, and who has texted me. On her end, the message came "over from a phone number rather than your name" = my phone #@mms.att.net. The format of her text was unconventional for a text as well We both have iPhones; I don't know which version she has, but mine is older, 4s, but relatively recent OS. I don't know her service provider either.
I received texts from others at about the same time as this message, and there was nothing unusual about those back & forths at all.
Why this anomaly? Is it an issue with her service or mine?