We have now discovered that even sending the "AT+CFUN=4" does not solve the problem. Yesterday we had a GPy stuck in a mode where it would not return the ICCID even after power on/off, modem reset command, and the AT+CFUN=4 command. The only thing that resolved the issue was to send a dummy attach command lte.attach(apn='unknown'). Then the lte.iccid() command worked from that point forward (even through power on/off and resets). We do not know what causes the GPy to get in this crazy mode; however, it seems to be related to low signal situations.