Quirky Map Crashes...any thoughts?

[Monstamash]

The past few weeks on my server I have been getting some strange crashes after a map change. Seems to happen randomly, but frequently, perhaps every 4 or 5 map changes...people vote on next map, or don't vote and it goes to the next map in the cycle, or an admin chooses the next map, but ~10 seconds after starting the new map, the server suddenly changes maps again to a random map...It does not happen on any one map in particular, and the map it changes to is not the same every time either. Even more interestingly, yesterday when it did this, it loaded up de_dust, which is not in my maplist, mapcycle, or votemaplist. Dust is on the server still, but I took it out of the rotation b/c it was overplayed. Anyone got any ideas here?

I am running a Linux based CSS server. Thanks!