While debugging the peculiar problem that linux and windows could mount but macosx could not mount shares I ran into the following.
For historic reasons my samba server has multiple alias interfaces with various ips in the same subnet. Specifiying in the config I could limit samba to run on the proper alias interface and ip address. After checking the output off "nmblookup -U woodstock -R woodstock" I noticed all three alias interfaces showed up in the list. After adding those alias interfaces to the smbd config apple computers could mount samba shares again.
Since this is trivial to reproduce I would like to request the developers of samba to see if this bug also applies to recent versions of samba.
To descibe the expected behaviour: If one alias is defined in the configuration only the specific ip that goes with that alias interface should be reported by nmbd.