Google Cardboard with an iPhone (iPhone = LCD screen) never made me sick per se, but the way everything blurred when I turned my head was dizzying, which discouraged actually looking around. It wasn't something I'd ever want to do for more than ten minutes.
I'm lucky in that I'm basically immune to VR sickness, but there's a large divide between "not sick" and "actually pleasant"
I haven't used it much, but when I tried Google Cardboard, the thing that made me sick was the lack of proper head tracking. Sure rotation worked....fine....but the real killer is when my head moved forward or backward and it didn't know how to account for it.
I won't try to assume what you experienced, but is it possible that perhaps that blurriness you saw was orthogonal to the discomfort you experienced from poor head tracking?