doveadm index panic

Hi,

running dovecot 2.2.18. when I try to re-index my INBOX I get following error:

# doveadm index -u user@domain.com INBOX doveadm(user@domain.com): Warning: I/O leak: 0x80101ada0 (line 120, fd 15) doveadm(user@domain.com): Warning: Timeout leak: 0x801019fe0 (line 325) doveadm(user@domain.com): Panic: file ioloop.c: line 39 (io_add_file): assertion failed: (callback != NULL) zsh: abort doveadm index -u user@domain.com INBOX

Any ideas?

Rgds, N.