Make logs in module cron

[NETIM]

We have developped our domain registrar module and we are facing an issue when using the module cron function.

in the function cron(), we are unable to write logs by using the regular $this->log() function. We assume there is no error but nothing is written.
We get only this
Attempting module cron for netim netim_async.
Finished module cron for netim netim_async. 

The turnaround is to throw an exception l
throw new Exception(".....");
In such case , our content is written but the backtrace also.

This is not a big issue, the turnaround works but it is not a proper solution.

Is it an issue with module crons ?
Is there a better way to write logs in module cron() function ?