Hi g67261831,
Looking around it seems to be a bug in
Thunar when the
gvfs* packages are installed.
Here is posted a solution to this, in the answer #17:
sudo mousepad (or leafpad, or gedit, or whatever) /usr/shares/gvfs/mounts/network.mount, and set AutoMount=false
Notice: the issue will come back if you open the
Network shortcut in the left side pane of a window.
So, if you don't use
samba/smb, then you could remove the
gvfs-backends package (i think, LOL).
Try to search deeper, maybe there is a better soulution...
Also be sure to be up to date with the distro.

Bye.
Have fun!