activa lt/softgel user question?

Last night I switched out the Activa LT cushion for the Softgel. They are interchangeable and fit in the same frame. My question is, the softgel cushion fits into the dk. blue plastic framepiece everywhere except for about an inch across the very bottom. There it just sits flush on the clear plastic. If you push it slightly it gaps, is this normal? I'm not sure if you know what I am trying to explain/ask.

Yes, that is the way mine is, too. It looks as though it shoul leak there, but it doesn't.