dovecot only partially indexing ... fts

[Infoomatic]

hi,
I have a setup using solr as fts, however it seems that when I move messages it does not automatically index the stuff. Also, when using sieve scripts to store messages in different folders I get:
dovecot: indexer-worker(user): Indexed 0 messages in testfolder

If I get a mail to normal INBOX I get 
dovecot: indexer-worker(user): Indexed 1 messages in INBOX

doveadm index -u user '*'
does the trick, however, I have set "fts_autoindex = yes" ... the relevant part of doveconf -n:

mail_plugins = fts fts_solr zlib acl quota zlib fts fts_solr acl
plugin {
  fts = solr
  fts_autoindex = yes
  fts_solr = url=http://localhost:8983/solr/ break-imap-search
  sieve = ~/.dovecot.sieve
  sieve_dir = ~/sieve
  sieve_extensions = +notify +imapflags
}
protocol lda {
  mail_plugins = fts fts_solr zlib sieve acl
}
protocol imap {
  mail_plugins = fts fts_solr zlib acl quota imap_acl imap_quota
}

is this normal behaviour or did I screw something up? 

TIA,
infoomatic