Loss of LTE on T-Mobile while on a voice call

I've had the Moto G 2015 for a few weeks now and noticed something strange. Whenever I get a call I immediately lose LTE and drop down to 3G (This phone does not tell you what kind of 3G you are on, probably HSPA+ but not sure). When the call is over it takes a while to get back on an LTE signal. The phone is 100% stock, and I'm on TMO post-paid in Southern Cali. Any thoughts?