Samba Regression - Mac OS X machines can't connect (Same issue as #1572301)

[noisymime]

I am still experiencing the issue reported in bug #1572301 on 14.04.1. samba package has been updated to 4.3.9+dfsg-0ubuntu0.14.04.1 however the exact issue remains. OSX clients (10.11.x) unable to connected as Guest.

Have tested on a 15.10 machine and issue is resolved, but on 14.04.1 with updated package the same problem appears to be occurring.

josh@blinky:~/Downloads$ dpkg -l samba | grep ^i
ii samba 2:4.3.9+dfsg-0ubuntu0.14.04.1 i386 SMB/CIFS file, print, and login server for Unix

With log level 2 on:
[2016/05/17 20:52:32.684883, 2] ../source3/param/loadparm.c:2686(lp_do_section)
  Processing section "[mythdata2]"
[2016/05/17 20:52:32.685088, 2] ../source3/auth/auth.c:315(auth_check_ntlm_password)
  check_ntlm_password: Authentication for user [GUEST] -> [GUEST] FAILED with error NT_STATUS_NO_SUCH_USER
[2016/05/17 20:52:32.685167, 1] ../auth/ntlmssp/ntlmssp_server.c:910(ntlmssp_server_postauth)
  ntlmssp_server_postauth: invalid NTLMSSP_MIC for user=[GUEST] domain=[] workstation=[MACBOOKPRO-2535]
[2016/05/17 20:52:32.685184, 1] ../lib/util/util.c:559(dump_data)
  [0000] 32 40 4C 9E FF 7D FC B1 D1 E8 BE A3 1F 2F 74 B2 2@L..}.. ...../t.
[2016/05/17 20:52:32.685249, 1] ../lib/util/util.c:559(dump_data)
  [0000] E3 92 9C 64 F5 D0 28 6D E2 D2 C3 B3 CC FC 71 47 ...d..(m ......qG
[2016/05/17 20:52:32.685282, 2] ../auth/gensec/spnego.c:708(gensec_spnego_server_negTokenTarg)
  SPNEGO login failed: NT_STATUS_INVALID_PARAMETER