Okay, here's the weird thing. I downloaded a simple Cookie Cutter STL from Thingiverse. I opened it in Cura and it let me slice it fine. But then when I went back to the sliced file, just to view it in Cura, half of Cookie Cutter was missing. This is what's been happening. When I do the print, they are only coming out half printed even though it looks like I'm slicing the entire object. But then when I reopen the very file I tried to print to see why it's not printing. Only half the file is showing - it looks just like it's printing out. Half a print.