WiFi and LTE Symbols

[NismoZ]

I've noticed something on this phone on ATT. Most of the time I have WiFi on, as to not use my data. When WiFi is on, I just see that symbol and no LTE symbol like I would expect. However, even now and then, when I have the WiFi symbol, there will also be a 4G LTE symbol next to it as well. That symbol isn't making the data animation, like it's using data, but it does show up. Do we know the reason for this or what makes it show up?

 

[Eclipse2K]

Usually when you receive an MMS that will happen. Other random things may cause it too but not sure what. Doesn't actually mean data is being used.

Samsung Galaxy Note 3 (Verizon)