Why does my soft body shrink?

It’s large, and it’s extremely small when I run it in the game engine.
Why? Rigid or static doesn’t do that… In fact, now it decided to start flying into the air!

How annoying!
This is more infuriating than it should be.
I cannot figure this out.

SUCH… A simple problem… And no one… willing to answer…

could you post the model, or at least a screen shot of your settings?