child processing timeout

[Ronan <r....@qub.ac.uk>]

getting quite a few of the following in the logs which are letting 
messages through unscanned.
running a dedicated server serving 3 mtas.
SA 3.1
MTA exim 4.54

Nov  3 03:05:44 dung spamd[11633]: spamd: bad protocol: header error: 
(Content-Length mismatch: Expected 29131 bytes, got 2
0440 bytes) at /usr/bin/spamd line 1671, <GEN600> line 461.
Nov  3 03:05:53 dung spamd[12035]: spamd: bad protocol: header error: 
(Content-Length mismatch: Expected 65351 bytes, got 2
0440 bytes) at /usr/bin/spamd line 1671, <GEN96> line 707.
Nov  3 03:05:54 dung spamd[12042]: spamd: bad protocol: header error: 
(Content-Length mismatch: Expected 25206 bytes, got 2
0440 bytes) at /usr/bin/spamd line 1671, <GEN66> line 295.
Nov  3 03:06:02 dung spamd[12046]: spamd: bad protocol: header error: 
(Content-Length mismatch: Expected 29131 bytes, got 2
0440 bytes) at /usr/bin/spamd line 1671, <GEN69> line 461.
Nov  3 03:06:07 dung spamd[12044]: spamd: bad protocol: header error: 
(Content-Length mismatch: Expected 25295 bytes, got 2
0440 bytes) at /usr/bin/spamd line 1671, <GEN87> line 294.
Nov  3 03:06:08 dung spamd[12046]: spamd: bad protocol: header error: 
(Content-Length mismatch: Expected 25401 bytes, got 1
7520 bytes) at /usr/bin/spamd line 1671, <GEN76> line 258.




Nov  3 03:21:28 dung spamd[12035]: bayes: child processing timeout at 
/usr/bin/spamd line 1085.
Nov  3 03:21:28 dung spamd[12042]: bayes: child processing timeout at 
/usr/bin/spamd line 1085.
Nov  3 03:21:51 dung spamd[11946]: bayes: child processing timeout at 
/usr/bin/spamd line 1085.
Nov  3 03:21:51 dung spamd[12039]: bayes: child processing timeout at 
/usr/bin/spamd line 1085.
Nov  3 03:22:02 dung spamd[12046]: bayes: child processing timeout at 
/usr/bin/spamd line 1085.
Nov  3 03:22:02 dung spamd[12043]: bayes: child processing timeout at 
/usr/bin/spamd line 1085.

Anyone have this or care to guess what it could be?