EP06-A 'AT+COPS=?' failing to report network operators

I am using EP06-A (version: EP06ALAR02A08M4G).

I am having issues with ‘AT+COPS=?’ failing after successful registration/connection/activation with a returned ‘CME ERROR: 3’ even though other network cmds like ‘AT+COPS?’, ‘AT+QNWINFO’, ‘AT+CREG?’, ‘AT+CEREG?’, ‘AT+CGREG?’, ‘AT+QENG=“servingcell”’, ‘AT+CGATT?’, etc. all return responses that show a successful network connection and activated PDP session.

I’ve tried to use qmicli -d <path to device> --nas-network-scan and that eventually fails with an abort message.

Are there any known issues with this AT command on this firmware version?

Thinking about this, I recall from the past that some modems will refuse to do a network scan while there is an active data connection. I don’t remember what those modems were, but I’m reasonably sure that at least some weren’t Quectels.

Testing with my RM500Q reveals that AT+COPS=? does work and get a result. But the data connection is completely unresponsive until the scan completes.

The difference in behaviour may be due to differences in the Qualcomm chipsets being used. But that’s speculation.