CentOS - Oct 2014 - DKIM mails from this mailing lists

Hi,

I've got some problem receiving mails from this list. Now and then the 
mails received from this list have an invalid dkim header. Therefore 
they are rejected by my MTA.
This causes me missing same mails and from time to time I get some mail 
saying:

Your membership in the mailing list CentOS has been disabled due to
excessive bounces.

What is going wromg here? Can the Mailing List Software be optimized to 
handle DKIM properly?


Thanks

Markus Steinborn