Please look in /var/log/moblock-control.log what is happening at the time when moblock reloads. From moblock-control this will only happen on "update" (either manually or by the cron job) or "reload".
I'm not the author of MoBlock (the daemon). Maybe there is something built in there that reloads it frequently.
Moblock-control.log doesn't say anything about reloading, but moblock.log gives following statement:
Fri Oct 31 13:00:10| Got SIGHUP! Dumping and resetting stats, reloading blocklist