There were many different kinds, I did not keep a copy. The issue is mails with bad-headers from whitelisted domains are still being quarantined. I want all mail from whitelisted domains to go through, even those with bad-headers. Is this possible? Is there a configuration for it?

I'll give you what I can for now, hang on for the rest

$ sudo postconf smtpd_recipient_restrictions
smtpd_recipient_restrictions = reject_unknown_recipient_domain, reject_non_fqdn_recipient, reject_unlisted_recipient, check_policy_service inet:127.0.0.1:7777, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination

$ sudo grep 'plugins' /opt/iredapd/settings.py
# Enabled plugins.
# - Plugin name is file name which placed under 'plugins/' directory,
# - Plugins are applied in specified order. It's better to list plugins which
#   white/blacklist related plugins, e.g. amavisd_wblist.
# - Suggested order of plugins (if you enable them) for RCPT state:
plugins = ["reject_null_sender", "amavisd_message_size_limit", "amavisd_wblist", "sql_alias_access_policy"]

iredapd log of quarantined mail:

2015-07-24 06:36:58 DEBUG smtp session: request=smtpd_access_policy
2015-07-24 06:36:58 DEBUG smtp session: protocol_state=RCPT
2015-07-24 06:36:58 DEBUG smtp session: protocol_name=ESMTP
2015-07-24 06:36:58 DEBUG smtp session: client_address=10.0.0.169
2015-07-24 06:36:58 DEBUG smtp session: client_name=ip-10-0-0-169.ap-southeast-1.compute.internal
2015-07-24 06:36:58 DEBUG smtp session: reverse_client_name=ip-10-0-0-169.ap-southeast-1.compute.internal
2015-07-24 06:36:58 DEBUG smtp session: helo_name=cluster-k.mailcontrol.com
2015-07-24 06:36:58 DEBUG smtp session: sender=aaa@aaa.com
2015-07-24 06:36:58 DEBUG smtp session: recipient=bbb@bbb.com.sg
2015-07-24 06:36:58 DEBUG smtp session: recipient_count=0
2015-07-24 06:36:58 DEBUG smtp session: queue_id=
2015-07-24 06:36:58 DEBUG smtp session: instance=490.55b1dd0a.a189d.0
2015-07-24 06:36:58 DEBUG smtp session: size=27152
2015-07-24 06:36:58 DEBUG smtp session: etrn_domain=
2015-07-24 06:36:58 DEBUG smtp session: stress=
2015-07-24 06:36:58 DEBUG smtp session: sasl_method=
2015-07-24 06:36:58 DEBUG smtp session: sasl_username=
2015-07-24 06:36:58 DEBUG smtp session: sasl_sender=
2015-07-24 06:36:58 DEBUG smtp session: ccert_subject=
2015-07-24 06:36:58 DEBUG smtp session: ccert_issuer=
2015-07-24 06:36:58 DEBUG smtp session: ccert_fingerprint=
2015-07-24 06:36:58 DEBUG smtp session: ccert_pubkey_fingerprint=
2015-07-24 06:36:58 DEBUG smtp session: encryption_protocol=TLSv1.2
2015-07-24 06:36:58 DEBUG smtp session: encryption_cipher=ECDHE-RSA-AES256-GCM-SHA384
2015-07-24 06:36:58 DEBUG smtp session: encryption_keysize=256
2015-07-24 06:36:58 DEBUG --> Apply plugin: reject_null_sender
2015-07-24 06:36:58 DEBUG <-- Result: DUNNO
2015-07-24 06:36:58 DEBUG Skip plugin: amavisd_message_size_limit (protocol_state != RCPT)
2015-07-24 06:36:58 DEBUG --> Apply plugin: amavisd_wblist
2015-07-24 06:36:58 DEBUG Possible policy senders: ['@.', 'aaa@aaa.com', '@aaa.com', '@.aaa.com', '@com', '@.com', '10.0.0.169', '10.*.0.169$
2015-07-24 06:36:58 DEBUG Possible policy recipients: ['@.', 'bbb@bbb.com.sg', '@bbb.com.sg', '@.bbb.com.sg', '@com.sg', '@.com.sg', '@sg', '@.sg', 'bbb@*']
2015-07-24 06:36:58 DEBUG SQL: Get policy senders: SELECT id,email FROM mailaddr WHERE email IN ('@.', 'aaa@aaa.com', '@aaa.com', '@.aaa.com$
2015-07-24 06:36:58 DEBUG Senders (in sql table: amavisd.mailaddr): [(210L, '@aaa.com')]
2015-07-24 06:36:58 DEBUG SQL: Get policy recipients: SELECT id,email FROM users WHERE email IN ('@.', 'bbb@bbb.com.sg', '@bbb.com.sg', '@.bbb.com.sg', '@com.sg', '@.$
2015-07-24 06:36:58 DEBUG Recipients (in `amavisd.users`): [(1L, '@.')]
2015-07-24 06:36:58 DEBUG SQL: Get wblist: SELECT rid,sid,wb FROM wblist WHERE sid IN (210) AND rid IN (1)
2015-07-24 06:36:58 DEBUG Found per-recipient white/blacklists: [(1L, 210L, 'W')]
2015-07-24 06:36:58 DEBUG <-- Result: OK wblist=(1, 210, 'W')
2015-07-24 06:36:58 INFO [10.0.0.169] RCPT, aaa@aaa.com -> bbb@bbb.com.sg, OK wblist=(1, 210, 'W')
2015-07-24 06:36:58 DEBUG Session ended

Mail Headers
Content-Type    multipart/mixed; boundary="----=_NextPart_000_1437719817"
Date    24 JUL 15 06:36:57 UT
From    aaa@aaa.com
MIME-Version    1.0
Message-Id    <201507240636.t6O6avNf011361@wm.aaa.com>
Received    from 172.10.138.71 ([10.138.20.52]) by wm.aaa.com (8.12.11/8.12.11) with SMTP id t6O6avNf011361; Fri, 24 Jul 2015 14:36:57 +0800
Received    from cluster-k.mailcontrol.com (ip-10-0-0-169.ap-southeast-1.compute.internal [10.0.0.169]) by mx.bbb.com.sg (Postfix) with ESMTPS id B7FD760752 for <bbb@bbb.com.sg>; Fri, 24 Jul 2015 06:36:58 +0000 (UTC)
Received    from mx.bbb.com.sg ([127.0.0.1]) by mx.bbb.com.sg (mx.bbb.com.sg [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id zqe2cwOXqqZm for <bbb@bbb.com.sg>; Fri, 24 Jul 2015 06:36:58 +0000 (UTC)
Received    from wm.aaa.com ([103.228.100.71]) by rly03k.srv.mailcontrol.com (MailControl) with ESMTP id t6O6av3Q016385 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 24 Jul 2015 07:36:57 +0100
Subject    CENSORED
To    bbb@bbb.com.sg
To    ccc@ccc.sg
X-Amavis-Alert    BAD HEADER SECTION, Duplicate header field: "To"
X-Envelope-To    <bbb@bbb.com.sg>
X-Envelope-To-Blocked    <bbb@bbb.com.sg>
X-Quarantine-ID    <zqe2cwOXqqZm>
X-Scanned-By    MailControl 44278.224 (www.mailcontrol .com) on 10.75.0.113
X-Spam-Flag    NO
X-Spam-Level   
X-Spam-Score    0
X-Spam-Status    No, score=x tag=x tag2=x kill=x tests=[] autolearn=unavailable

$ grep '@lookup_sql_dsn' /etc/amavis/conf.d/50-user
@lookup_sql_dsn = @storage_sql_dsn;

Yes, I understand why the header is bad. My question is why does the whitelist not allow this email to go through? Yes, I have disabled bad header quarantining because whitelisting is not working for bad headers.