[Samba] ntlm_auth broken under Samba 4.18.6

[Zombie Ryushu]

Since upgrading to OpenSuse 15.5, I've had issues with ntlm_auth when 
running Samba 4.18.6 as an ADDC. This is new behavior that wasn't 
present in 4.13.3

ntlm_auth --username=zombie --diagnostics
Password:
Reading winbind reply failed! (0xc0000001)
Reading winbind reply failed! (0xc0000001)
diagnose_ntlm_auth: Test LM and NTLM failed!
Reading winbind reply failed! (0xc0000001)
diagnose_ntlm_auth: Test NTLM failed!
Reading winbind reply failed! (0xc0000001)
diagnose_ntlm_auth: Test NTLM in LM failed!
Reading winbind reply failed! (0xc0000001)
diagnose_ntlm_auth: Test NTLM in both failed!
Reading winbind reply failed! (0xc0000001)
diagnose_ntlm_auth: Test NTLMv2 failed!
Reading winbind reply failed! (0xc0000001)
diagnose_ntlm_auth: Test NTLMv2 and LMv2 failed!
Reading winbind reply failed! (0xc0000001)
diagnose_ntlm_auth: Test LMv2 failed!
Reading winbind reply failed! (0xc0000001)
diagnose_ntlm_auth: Test NTLMv2 and LMv2, LMv2 broken failed!
Reading winbind reply failed! (0xc0000001)
Reading winbind reply failed! (0xc0000001)
diagnose_ntlm_auth: Test NTLM and LM, LM broken failed!
Reading winbind reply failed! (0xc0000001)
Reading winbind reply failed! (0xc0000001)
diagnose_ntlm_auth: Test Plaintext failed!
Reading winbind reply failed! (0xc0000001)
diagnose_ntlm_auth: Test Plaintext LM broken failed!
Reading winbind reply failed! (0xc0000001)
Reading winbind reply failed! (0xc0000001)
diagnose_ntlm_auth: Test Plaintext NT only failed!
Reading winbind reply failed! (0xc0000001)