Add 'Cron Scheduled Tasks' in 'servers' (not admin) with code:
if using xen/kvm/dedi:
sh /script/clearcache --select=1; sh /script/restart
or (if using openvz):
sh /script/restart
where set for every day or every 3 hours.
In early Kloxo-MR, this issue tend to not appear. Possibility:
1. Centos
2. lxphp
3. lxlighttpd
I will try alternative using nginx+php52s instead lxlighttpd + lxphp.