Update: It appears to have something to do with the deltion module. I've tweaked the deletion settings but, the zombies still despawn after approximately 30 secs. If I remove the deletion module, altogether, the issue is resolved. I've done so much as to put 1 spawner down, set it to an activation distance of 300m then set the deletion to 1000m. I can be standing 200m from the spawner and they still despawn after 30 secs. Any help or suggestions would be appreciated. I'm neck deep in a massive survival mission build and this has absorbed much of my time while attempting to troubleshoot it.

Last Arma update broke Z&D. Seems like nothing we can do but just wait for another update that will hopefully fix that.

Ah, ok. Thanks for the reply. Hopefully it will be fixed soon. :)

Updated.

MrSanchez, you just made my day. Thanks for working on it and resolving the issue.