Well, after tightening up the 2 MFL connections, things look to be stable so that is good. I guess I didn't know you could tighten those any tighter than just by hand. I figured it would crush the flared nylon washer inside.
Also, after they were tightened, the hose no longer moved on the barb. I think what was going on was that the barbed swivel nut was loose enough that the barbed end could rotate so it made it look like the hose was not tight. Once the MFL connection was tightened, the barbed end of the swivel nut was immobilized and now the hose can't turn.