Call sub process in an iteration, sub process never calls

Hello,

I have a process witch call a sub process. The calling task has an iteration on a list of a complex object creating from my Data Model.

When I launch the root process, the sub process is never called. 

I know my list, used for the iteration, is correctly filled. I log its content and I see some data in it.

I set some logs at the beginning of the sub process and they are never write when I display the logs.

Moreover, I don't see any errors in the log so I don't understand why my sub process is never called.

Somebody have already encountered this kind of issue ?

Thanks by advance