Why are you so sure that the 4G OP is experiencing is NOT LTE?
The OP says he's referring to 4G
LTE, so I'm not sure what your question means.
Here are three reasons I'm convinced there's currently non-LTE 4G (WiMax) still live:
1. It's still on
Sprint's coverage map, with cities that don't have LTE showing WiMax.
2. Many older phones don't have LTE bands, but the users are still using 4G (WiMax)
3. FWIU some phones indicate LTE coverage separately (different network icon).