I don’t know what happened to your module, but in some way your module seems to have been re-downloaded with a new firmware. Which at some point erase the module customization and/or something else.
The number you’re seeing is link to a default value that Sierra Wireless is loading in the module when people ordered module without IMEI specifically (some people like to use their own IMEI range).
When your module has this value, it allows you a one time programming of an IMEI value.
So, if your module is supposed to be with an IMEI (like what is written on th esticker), it means that in some way something happened to it. Or the IMEI customization didn’t work somewhere.
Anyway, if it is the only module you have like that, you should be able to reflash your IMEI with the command AT+WIMEI. Take care to don’t write any mistake, it is a one time programming. But it is difficult to know if it is the only bad stuff in your module.