Comment 5 for bug 1872476

When you are connected with the GUI and seeing all files as browsers, can you please run smbstatus on your NAS to see what protocol version was used?

NT1 is used for browsing when you set that option, but the client (your machine) might switch to a higher version if the NAS says it supports it.

For example, I just tried with a 20.04 install, browser to my NAS (a synology DS216) using windows network, and when I actually connected to a share, smbstatus on the server says it used SMB3_11:

root@ds216:~# smbstatus
29552 1587992052 andreas 10.10.1.230 downloads SMB3_11

Regarding your smbclient test, you didn't add the -m switch, so it's likely is used a higher protocol version.

Example:
a) no -m switch:
$ smbclient //ds216.lowtech/downloads
Enter WORKGROUP\andreas's password:
Try "help" to get a list of possible commands.
smb: \>

smbstatus on the NAS:
# smbstatus
29833 1587992358 andreas 10.10.1.195 downloads SMB3_11

b) with -m NT1:
$ smbclient //ds216.lowtech/downloads -m NT1
Enter WORKGROUP\andreas's password:
Try "help" to get a list of possible commands.
smb: \>

smbstatus on the NAS:
# smbstatus
29816 1587992342 andreas 10.10.1.195 downloads NT1