I suspect it's because of the springs in both cases being in tightly packed groups, where they may actually be setting each other off unintentionally... somehow. I'll get back to you on that, this is a curious issue here.
Oh good grief, they actually trigger other springs at the same time if you happen to be in normal gravity when triggering them, it turns out:
In particular they fling down only the next spring in order of item placement in the map. ...but they do this only when you're in normal gravity; when you're in reverse gravity they don't do this at all.
Curious findings, can't for the life of me figure out why this is happening firsthand.