Samba 4.8 changed default 'client max protocol' from NT1 to SMB3, together with fixes of Badlock, it broke browsing smb:// with default settings, because only NT1 (SMB1) protocol can browse network. Samba 4.10 made it possible to set min/max protocol version via libsmbclient API.
Similar to https://gitlab.gnome.org/GNOME/gvfs/commit/6c8bc39f570ea82cf14e83ce7d1dbdbe569d09d1