some childrens are stuck on 'compressing attachment'

[Marco Barbero]

Hi
Mailscanner 4.70.7
Postfix 2.5.5

I experienced a strange issue:  all my children stuck on 'compressing
attachment' so mailscanner stop to process queue.
Mailscanner was not able to restart children every 'time' set on
Mailscanner.conf.  So I had to kill processes and restart mailscanner.
Debug mode (spamassassin and mailscanner) didn't show any problem.  I
have other installations like this but never suffered a similar issue.
 Any hints?
At the moment I'm thinking about a workaround:  kill mailscanner every
30 minutes and restart it.  Is there any risk about mail and or bayes
corruption?
Thanks in advance