Difference in RSSI value between AT and MBIM query

I have observed that an EM7430 module will report two different values for RSSI depending on if it is queried via AT command or MBIM (‘signal state’ message). For example, it will report -77 dBm via AT+CSQ but -103 dBm via MBIM. Can anyone explain why this is so?

are you using EM7430?
have you compared with the RSSI in AT!GSTATUS?
Are you using latest FW to test?
Are you testing with LTE network?