Hidden field is displayed in submission email even after the field is removed form email template

Also, Spécial Savardises....(field) is showing in the notification even if I removed the line from the notification grid. it is a hidden field and should not be seen in the notification. (only appears in submission but not on pdf nor email notification

Do you mean the fields under Spécial Savardises collapse/heading? You have three fields under this section which are present in the notifications of the form. You have the following:

If you do not want these fields to appear in the email, you have to delete them. You said you removed the fields, but I think you removed the others. Please review.

You should know it by checking the field names: https://www.jotform.com/help/146-How-to-Find-Field-IDs-and-Names.