I think it's entirely possible that you know more than the AT&T engineers that i spoke with. So, you should call them and tell them how to fix this "bug" you found.
Well
of course the "tech" would never just buffalo his way thru it enough satisfy you (just hypothetical of course) because maybe has no idea what the problem is and might be just a service rep not an engineer.
Not saying this is the case but criticizing someone else's theory all because a company that wants your money "said so" is just crazy thinking. (SMH) I hope you don't still decide that things must be true based on one person saying so.. Although, hey if you do would you believe I've got some ocean front property for sale in Arizona at a special low price just for you.. Well, of course I'm telling you the truth. I mean you did read it on the internet didn't you.. and we all know the internet doesn't lie. B-)