I changed it to v3 same result.
as far as i know there's two places where you can set smb version. In the libreelec settings (min-max) and in kodi service settings (cant check right now but i believe that is correct).
I set the LE config to min: smbv2, max: smbv3. In Kodi services i set max to smbv3. That works here.
Also, i think that some nas systems require smbv1 to function