[exim] Exim: spam acl condition: cannot parse spamd output

I have just upgraded my Spamassassin on Debian Stable to 3.1.3
(backports) from 3.0.3 and I get this message in Exim's paniclog:

spam acl condition: cannot parse spamd output

That is not the case with every message. Does

My Exim4-acl's:

warn message = X-Spam-Score: $spam_score ($spam_bar)
          condition = ${if <{$message_size}{100k}{1}{0}}
          hosts = ! +relay_from_hosts
          spam = spamd:true

warn message = X-Spam-Status: YES
          hosts = ! +relay_from_hosts
          condition = ${if <{$message_size}{100k}{1}{0}}
          condition = ${if >{$spam_score_int}{80}{1}{0}}
          spam = spamd:true

warn message = X-Spam-Status: NO
          hosts = ! +relay_from_hosts
          condition = ${if <{$message_size}{100k}{1}{0}}
          condition = ${if <{$spam_score_int}{80}{1}{0}}
          spam = spamd:true

warn message = X-Spam-Flag: YES
          hosts = ! +relay_from_hosts
          condition = ${if <{$message_size}{100k}{1}{0}}
          condition = ${if >{$spam_score_int}{80}{1}{0}}
          spam = spamd:true

warn message = X-Spam-Flag: NO
          hosts = ! +relay_from_hosts
          condition = ${if <{$message_size}{100k}{1}{0}}
          condition = ${if <{$spam_score_int}{80}{1}{0}}
          spam = spamd:true

warn message = X-Spam-Report: \n $spam_report
          hosts = ! +relay_from_hosts
          condition = ${if <{$message_size}{100k}{1}{0}}
          spam = spamd:true

# reject messages that score more than 8
   deny message = Message viewed as spam. (scored $spam_score) \n \
             If you are convinced that it was not spam, please send \n \
             it again and this time CC it to sysadm@??? or \n \
             contact sysadm@??? to find out why it was marked as \n\
             spam.  The system administrator will require the following \n \
             information: sender address, recipient's address and time.
          hosts = ! +relay_from_hosts
         spam = spamd:true
          condition = ${if eq{$acl_m0}{t}{yes}{no}}
          condition = ${if <{$message_size}{100k}{1}{0}}
          condition = ${if >{$spam_score_int}{80}{1}{0}}
          log_message = SPAM: Message viewed as spam. (scored $spam_score)

    
Any idea what is causing this?

Regards
Johann
-- 
Johann Spies          Telefoon: 021-808 4036
Informasietegnologie, Universiteit van Stellenbosch

     "For God hath not appointed us to wrath, but to obtain 
      salvation by our Lord Jesus Christ, Who died for us, 
      that, whether we wake or sleep, we should live  
      together with him."     
                         I Thessalonians 5:9,10