[Dovecot] stable assert error

[Paul Jongsma]

Hello,

When moving a message from my inbox to an existing mailbox folder I get:

dovecot: Mar 21 12:52:48 Error: IMAP(paulj): file istream-raw-mbox.c: 
line 383 (istream_raw_mbox_get_body_size): assertion failed: 
(rstream->body_offset != (uoff_t)-1)
dovecot: Mar 21 12:52:48 Error: child 10265 (imap) killed with signal 6


This after moving from 0.99 to 1.0 stable  on 5.3-RELEASE-p5
Client is Apple Mail program

Anything I can do to fix or investigate?

Thanks
Paul