[Dovecot] Troubles with /.dovecot.lda-dupe on dovecot 2.1.5

Seems that is something with vacation message,

Apr 26 12:20:02 server dovecot: lmtp(26937, user@domain): Error: file_dotlock_create(/storage/domain/users/user/.dovecot.lda-dupes) failed: Resource temporarily unavailable Apr 26 12:20:02 server dovecot: lmtp(26937, user@domain): Fatal: master: service(lmtp): child 26937 killed with signal 11 (core dumps disabled) And its created a .dovecot.lda-dupes.lock

Any idea ?

Jean Michel Feltrin