That's a good idea, the hose is long enough to have developed a natural trap.
Isn't ice maker tubing copper? Is there any chance this will puncture my tubing? And, will I have to do it every time I turn of the sump pump?

I'm hoping shortening that tube will reduce the gurgle, if I remove the natural trap. I've gotten the drain pipe adjusted so it doesn't flush anymore, now it's just the gurgling I'd like to reduce.