Comment 31 for bug 1828107

In the very same article you linked: https://docs.microsoft.com/en-us/windows-server/storage/file-server/troubleshoot/smbv1-not-installed-by-default-in-windows

With SMBv1 being removed, Network Browser (which depended on SMBv1) was removed, all of which relied on NetBios being used for discovery. (Hence, NetBios is dead, long live NetBios).

Microsoft's replacement for NetBios discovery is *drumroll please*: WSD.

I'm completely speculating here but:
Your initial start up effect is probably gvfsd-smbd doing something like a Browser Tree scan of last known hosts. This actively goes to the host asking about available protocols, shares etc. This is NOT discovery. You could argue "well if it already knew about it, how does it lose it?" and that is a fair question, to which the answer might well be "Don't want to do an expensive back n forth poll, would rather use a discovery protocol", and now we are back to the discussion of needing a discovery protocol: WSD.