I see the relation, because it wasen't like that, so when i tryed to make the player to go underwater it started to happend, and gave me other errors...

Edit: indeed, i'm right. I removed you're code, and the models don't dissapear anymore. I'm checking what could be doing this, but i think it has to do with the flare.

Edit Again: When i'm on top of the mountain that problem with the player just dissapears... Strange...