Mesh acting weird, it randomly changes HELP!!

[Anonymous]

Hey guys,

I have attached 2 images. In the first image, is a model of a knife switch where the bottom of the blade is flat. Everything is good so far, now I imported the model into another scene (image 2). Initially the blade is fine but after a random amount of time the blade changes into a sharp edge. I tried importing it multiple times and eventually it ends up changing. ANY IDEAS?? HELP!!

[Its_jay]

first of all . open your scene(the scene have good mesh) try file / optimize scene size

than export your fine mesh as (FBX)