[Dovecot] error with xz compression

[Michael Cramer]

i have enabled the zlib plugin with xz compression but on some new  
mails i got now a segfault and the following lines in dovecot error.log

Dec 12 08:51:23 imap(tester at domain.com): Error:  
lzma.read(/srv/vmail/mail/domain.com/root/storage/m.3): unexpected EOF  
at 136004
Dec 12 08:51:23 imap(tester at domain.com): Error:  
read(zlib(/srv/vmail/mail/domain.com/root/storage/m.3)) failed:  
Invalid argument (uid=2985)
Dec 12 08:51:23 imap(tester at domain.com): Error: mail parser:  
read(zlib(/srv/vmail/mail/domain.com/root/storage/m.3),  
box=Shared/root at domain.com) failed: Invalid argument
Dec 12 08:52:33 indexer-worker(tester at domain.com): Error:  
lzma.read(/srv/vmail/mail/domain.com/tester/storage/m.41): unexpected  
EOF at 4913758

the problem is that the mails can't be shown. this happens not with  
every mail i also got new mails that can be shown without any problem.  
i was not able to produce a coredump