Collision Triggers at Random

Hey everyone,

I've got these lava pits that are supposed to burn the player up when he lands in them. It works great but sometimes it triggers at random.

Here is the code:

Here are some screen of it triggering when in the lava and when in mid air:

Is there something I'm doing wrong in my script?

The lava itself is a prefab that gets scaled in the scene to fill in any place where I need to it pool.

Any ideas would be greatly appreciated!