Tnt ignites but doesn't explode.

So I own a factions pvp server and we were going to test obsidian destroyer. We made a little obsidian room and put tnt in it, all it did was ignite then just disappeared. I went onto google to see if I could find the cause of the problem but to my amazement google didn't have the answer.

A list of my plugns below: If needed I can post my start up log.
-AutoBroadcaster
-ClearChat
-ClearLag
-CombatLog
-CommandCooldown
-CoreProtect
-CraftBukkitUpToDate
-EnjinMinecraftPlugin
-Essentials
-GAListener
-Groupmanager
-HealthBar
-KitPreview
-ObsidianDestroyer
-PlayerHeads
-PluginMetrics
-SilkSpawners
-SimpleRename
-Updater
-Votifier
-WorldBorder
-WorldEdit
-WorldGuard
-contrib
-McMMO

 

-WorldEdit
-WorldGuard

Probably one of these. Look for something like tnt-explosion: true/false (This isn't exact, but it will be similar).

It's probably something like that in WorldGuard config.