Testing of LTE network with USIM, but not able to scan LTE network in manual selection?

Recently i am testing LTE network and intially though of having problems with USIM card. But it turns out that the phone is the problem.

I am testing with 4 type of handsets, I-phone5, Galaxy S4, Blackberry Z10 and Huawei 4G modem. All of them supporting the LTE and frequency that we are using. Problem is that none of the phones , will switch to LTE network scan when this USIM is inserted. They show only 2G and 3G network.Frequency is there, because i have tested with spectrum analyzer, and the E-NodeB is behaving correctly.
Meanwhile when testing with one U-SIM from AT&T, all the handset can tune them self and show 4G signal on Manual Selectio mode.
I am thinking on 2 possible scenarios:
1. All these branded phones have some white list, of MCC MNC list of the carriers that support LTE. ( but then how is supposed to do some operator testing in advance, before publishing it to GSMA )
2. The U-SIM recently produced might have something wrong in the electrical profile, that is not giving any indication to the phone about the present of USIM , instead of SIM, thus stating the check for 4G frequency as well.

Anybody experiencing the same??