@tomerg,
EM74x1 differ from EM7455/EM7430 in that they use a newer Qualcomm chipset and are therefore running a different firmware.
My understanding is that you are using your own custom LPA. If this is correct my suggestion would be switch to QMI-over-MBIM tunneling und the QMI UIMSAP* functionality as mentioned here EM7455 with OC1120 - AT+CSIM error or use MBIM UICC_RESET with PassThrough before the other MBIM UICC requests to avoid potential side effects.
Regards,
Reinhard