I have this issue also. Seems we are one big happy family with the 8xt. I haven't combed through the threads but was curious if you get repeated texts in a loop even when people aren't texting you? For instance, I get a text (get media content now) and I periodically get a text from the same sender and can't stop it. Is this part of your symptoms also?
That has happened to my wife's 8XT, not mine...she's running on CDMA only now, until this gets fixed. I still manually switch LTE off/on when I need to get a group message.