trouble when changing task status

Hello,

We are moving from using event to use Task, 

In sandbox I created a workflow rules to update the subject of a Task when the status is changed, it was working well.

I tried to do it in production but when I update the Task Status the Task get "mark as done"(like the checkbox is checek and the subject is struck out) like the first one on the picture. 

I would like to desactivate this feature so I can use my workflow rule but I don't know where to find it ...

Do you know where I can find it or how to do it ?

Thanks in advance !

Yann

#Tasks  #Task Quick Actions  #Task Management  #Data Management  #Quick Actions  #Sales Cloud