What are the possibilities that an Entity can has a wrong bounding hull?

Of all my entities in my game, I have ONE very stubborn Entity. I create that Entity using MED just like the rest and call into Lite-C as usual.

While playing the game, when I press F11, I can't see any bounding box for that stubborn Entity but collision detection still works. It just that the bounding hull "feel" so high (I'm not sure the limit) because any entity pass over that stubborn Entity will collide. I need to lower down the bounding box.

Here's what I did:

Stubborn = ent_create("aCylinder.mdl", nullvector, NULL);
wait(1); c_setminmax(Stubborn);

What I didn't understand, supposedly, even we didn't c_setminmax, we should be able to see the bounding when we press F11.