Random/Weird size of BoundingBox


Im loading a 3ds model and the model boundingbox is varying its size apparently randomly.

Here is two screenshots of my game being run two times sequencially without any code change.

Here is the correct bounding box of the car:

Here is the weird bounding box of the car (taller):

Somebody knows why that happens? Is there a solution?

are there particles perhaps?

Not in this case, the weird bounding box seems to move with the rotation of the wheels but it doesnt rotate, it goes up and down only.

I will try to detail more when i get home.

I guess I've encountered the same behavior but can't say if it is normal.

My model is a cylinder with a fan on top of it. I make the fan rotate along the Y axis and the fan bounding box grows increase and decrease periodically.