[Exim] Exim 4.10 + exiscan-15 problem

We have a strange problem with our mailserver.

messages are getting left in the /var/spool/exim/input and msglog directory
as well as the virus scanner directory /var/spool/exim/scan

The contents of mailq does not reflect the contents of the input/msglog
directory which seems really strange.

We are using uvscan (mcafee) with exiscan. It seems to be occasionally
leaving scanned files behind and not removing them. Not all of them, just
some of them. I am wondering if theres a code problem somewhere.

Has anyone seen this happen before? What was the cure in your case? As you
might guess Im a bit bothered about it.

Everything else seems to work okay. No reports of missing messages so far.

Thanks

Andy