Can't use Underwater Weapons

I'm just wondering if anyone knows why you can't use weapons underwater? I've added the swimming pack, underwater, and trident to my main character but they can't use any weapons underwater (other then the assault rifle for some reason). And I'm trying to make it so they can only equip and attack with the underwater gun and trident underwater.

I'm also having the problem with the underwater gun and trident being using able when on land for some reason

Thanks for your help,
Does the demo scene work correctly? Does the Use ability activate?

The swimming demo scene disables the use ability when out of water.