Actually it looks like it won't save my settings. Weird, I'll try editing the settings in the registry manually.

Might I ask how you were able to keep it checked?

It confuses me because when I go to test another map, the zombies act just fine. All of the settings for the spawners are correct and I even tried to copy the spawners from a new map and still nothing.

I know it has something to do with my map, I'm just not sure what it is.
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I've been searching and came across this. http://steamcommunity.com/app/455130/discussions/0/350542683212730584/

Potato Salad's method worked for me. Let me know if this help you out.