[exim] spool format error: size

Hi there!

I get a lot of this errors:

4d  6.6K 1fhLuL-0003Kp-6q <systemd-devel-bounces@???>
    *** spool format error: size=7871 ***
          jakob@localhost

In the logs i find:
Jul 22 23:30:22 aldebaran exim[13430]: 2018-07-22 23:30:22
1fhLvq-0003Uc-Es SA: Debug: SAEximRunCond expand returned: 'true'
Jul 22 23:30:22 aldebaran exim[13430]: 2018-07-22 23:30:22
1fhLvq-0003Uc-Es SA: Debug: check succeeded, running spamc
Jul 22 23:30:22 aldebaran spamd[14259]: spamd: connection from localhost
[::1]:56224 to port 783, fd 5
Jul 22 23:30:22 aldebaran spamd[14259]: spamd: processing message
<9132e567-2594-4796-9af6-0a0f9132c4c7@???> for
Debian-exim:118
Jul 22 23:30:23 aldebaran spamd[14259]: spamd: clean message (-3.8/5.0)
for Debian-exim:118 in 0.9 seconds, 77991 bytes.
Jul 22 23:30:23 aldebaran spamd[14259]: spamd: result: . -3 -
DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HTML_FONT_LOW_CONTRAST,HTML_MESSAGE,RCVD_IN_DNSWL_BLOCKED,RCVD_IN_RP_CERTIFIED,RCVD_IN_RP_SAFE,RDNS_NONE,T_DKIMW
Jul 22 23:30:23 aldebaran exim[13430]: 2018-07-22 23:30:23
1fhLvq-0003Uc-Es SA: Action: scanned but message isn't spam: score=-3.8
required=5.0 (scanned in 1/1 secs | Message-Id:
9132e567-2594-4796-9af6-0a0f9132
Jul 22 23:30:23 aldebaran spamd[9813]: prefork: child states: II
Jul 22 23:30:23 aldebaran exim[13430]: 2018-07-22 23:30:23
1fhLvq-0003Uc-Es <=
bounce-13_HTML-36038220-640150-6222865-771@???
H=localhost (aldebaran.local) [127.0.0.1] P=esmtp S=80098
Jul 22 23:30:23 aldebaran fetchmail[4961]: Nachricht
me@???@pop.myprovider.net:5199 von 5231 wird gelesen (78698
Bytes) nicht gelöscht
Jul 22 23:30:23 aldebaran exim[13455]: 2018-07-22 23:30:23
1fhLvq-0003Uc-Es Format error in spool file 1fhLvq-0003Uc-Es-H: size=6808


I use btrfs as filesystem. But scrubbing the filesystem ends without any
error.

I have exim4 4.91-5 from debian/buster.

Maybe it is a problem of exim? Or does it com from spamassassin?


Jakob