As I point out, the folder /root/.acme.sh/cwp_certs, was the key here.
After reading the log file in /root/.acme.sh/acme.sh.log , it is clear to me (it would need confirmation from someone who
really knows how cwp handle cert with acme.sh), that the parameter "home" in the cron task, indicates to acme.sh where to start is renewal work.
/root/.acme.sh/acme.sh --cron --home /root/.acme.sh/cwp_certs > /dev/null
Every domain has its own folder in cwp_certs folder. In every of these folders, there is a file that ends ending with .conf (ex:
www.mydomain.com.conf).
In these files, you'll find many var, some of them are used by acme.sh to decide if it will or not, renew the domain.
Quick fix :
Go to the folder given as parameter 'home' to the cron task, and delete the folder of the domain.
This is not a bug fix.CWP should have deleted these folders when we removed the domain from CWP panel. This is the bug, and the provided "fix" does not repair the bug.