Nimbostratus
Cirrocumulus
Something to help troubleshoot - I've referenced this doc before and it's been of use:
http://support.f5.com/kb/en-us/solutions/public/7000/000/sol7024.html?sr=15954430
In there is says that these 3 daemons mcpd, cssd and httpd are used in the configsync process. It sounds like from your initial post that restarting httpd helped, I wonder if it was hogging the memory and a restart has gone some way to correct this?!?
I'd try to see how much cpu / mem all 3 are currently using on both boxes (ps -aux |grep httpd etc...)
Hope it sheds some light on the matter.
N