[exim] Quoting problem in string expansion with fancy header

Hi,

how can I prevent this error:
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1VPTGe-0006Ow-5x H=r22.email.someuser.com (r22.p4.someuser.net) [2.3.4.5] F=<someuser@???> temporarily rejected after DATA: failed to expand ACL string "${if eq {${lookup pgsql {SELECT * FROM record_Reception( warn#011#011condition = ${if eq {${lookup pgsql {SELECT * FROM record_Reception( '${quote_pgsql:$acl_m_mail_id_list}', '${quote_pgsql:$message_exim_id}', '${quote_pgsql:${if def:h_from:{$h_from:}{$h_sender:}}}', '${quote_pgsql:$h_Subject:}', '${quote_pgsql:$dkim_verify_status}', '${quote_pgsql:N/A}')}}}{t}}": missing } at end of string
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? The config fragment is:
---
  warn        set acl_m_tmp = no
  warn        condition = ${if eq {${lookup pgsql {SELECT * FROM record_Reception( \
                        '${quote_pgsql:$acl_m_mail_id_list}', \
                        '${quote_pgsql:$message_exim_id}', \
                        '${quote_pgsql:${if def:h_from:{$h_from:}{$h_sender:}}}', \
                        '${quote_pgsql:$h_Subject:}', \
                        '${quote_pgsql:$dkim_verify_status}', \
                        '${quote_pgsql:N/A}')}}}{t}}
            set acl_m_tmp = yes
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The headers (as recorded in the DB)
 are:
    \"Someuser\" <contact@???>
     Pricedrop - everything must go! Prices keep falling until sold!
---
The lookup succeeded, so I assume exim did some fallback with the expansion.

Thanks, Axel
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