Thanks you very much for your help !
First, a little question. Since I encounter this bug in Debian
Stretch, and as the bug behavior slightly change since the last Debian
stable security update ( see CVE-2017-14604 ). Do you think it's
better to report the bug on Debian's BTS first ?
If you are confident it has changed in a stable update, that is the correct thing to do, yes.
2) When I traverse inside /dns/parent with Nautilus. It do some sort
of file request as the two NFS referrals are mounted ( normally, from
terminal, they are mounted only when you enter them ).
I've not learned about NFS referrals, so I'm not sure if the same logic applies, but it seems wrong that something would be mounted just because you open the parent of the mountpoint.
Is the item count of folders (visible in the "Size" column under list view) enabled for remote locations? (There are controls for this in the Preferences dialog.)
4) To solve the problem I have three possibilities :
-> I can press F5 inside the "Ressource" folder.
-> If I press F5 before entering the "Ressource" folder the crosses
disappears. And when I enter the "Ressource" folder I can create
directories inside it.
-> If from any manner I go a second time inside the "Parent" folder.
The crosses disappears and I can create directories inside the
"Ressource" folder.
These observations suggest that nautilus keeps outdated metadata about the folder until forced to refresh it.
